On i965/g4x IIR is edge triggered. So in order for IIR to notice that
there is still a pending interrupt we have to force and edge in ISR.
For the ISR/IIR pipe event bits we can do that by temporarily
clearing all the PIPESTAT enable bits when we ack the status bits.
This will force the ISR pipe event bit low, and it can then go back
high when we restore the PIPESTAT enable bits.
This avoids the following race:
1. stat = read(PIPESTAT)
2. an enabled PIPESTAT status bit goes high
3. write(PIPESTAT, enable|stat);
4. write(IIR, PIPE_EVENT)
The end result is IIR==0 and ISR!=0. This can lead to nasty
vblank wait/flip_done timeouts if another interrupt source
doesn't trick us into looking at the PIPESTAT status bits despite
the IIR PIPE_EVENT bit being low.
Before i965 IIR was level triggered so this problem can't actually
happen there. And curiously VLV/CHV went back to the level triggered
scheme as well. But for simplicity we'll use the same i965/g4x
compatible code for all platforms.
Cc: stable@vger.kernel.org
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106033
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105225
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106030
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180611200258.27121-1-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
(cherry picked from commit 132c27c97c)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Interrupts other than the one for AUX errors are required only for debug,
so unmask them via debugfs when the user requests debug.
User can make such a request with
echo 1 > <DEBUG_FS>/dri/0/i915_edp_psr_debug
There are no locks to serialize PSR debug enabling from
irq_postinstall() and debugfs for simplicity. As irq_postinstall() is
called only during module initialization/resume and IGT subtests
aren't expected to modify PSR debug at those times, we should be safe.
v2: Unroll loops (Ville)
Avoid resetting error mask bits.
v3: Unmask interrupts in postinstall() if debug was still enabled.
Avoid RMW (Ville)
v4: Avoid extra IMR write introduced in the previous version.(Jose)
Style changes, renames (Jose).
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Jose Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180405013717.24254-1-dhinakaran.pandiyan@intel.com
Currently, we rely on inspecting the hangcheck state from within the
i915_reset() routines to determine which engines were guilty of the
hang. This is problematic for cases where we want to run
i915_handle_error() and call i915_reset() independently of hangcheck.
Instead of relying on the indirect parameter passing, turn it into an
explicit parameter providing the set of stalled engines which then are
treated as guilty until proven innocent.
While we are removing the implicit stalled parameter, also make the
reason into an explicit parameter to i915_reset(). We still need a
back-channel for i915_handle_error() to hand over the task to the locked
waiter, but let's keep that its own channel rather than incriminate
another.
This leaves stalled/seqno as being private to hangcheck, with no more
nefarious snooping by reset, be it whole-device or per-engine. \o/
The only real issue now is that this makes it crystal clear that we
don't actually do any testing of hangcheck per se in
drv_selftest/live_hangcheck, merely of resets!
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Jeff McGee <jeff.mcgee@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180406220354.18911-2-chris@chris-wilson.co.uk
BSpec says:
"Second level interrupt events are stored in the GT INT DW. GT INT DW is
a double buffered structure. A snapshot of events is taken when SW reads
GT INT DW. From the time of read to the time of SW completely clearing
GT INT DW (to indicate end of service), all incoming interrupts are logged
in a secondary storage structure. this guarantees that the record of
interrupts SW is servicing will not change while under service".
We read GT INT DW in several places now:
- The IRQ handler (banks 0 and 1) where, hopefully, it is completely
cleared (operation now covered with the irq lock).
- The 'reset' interrupts functions for RPS and GuC logs, where we clear
the bit we are interested in and leave the others for the normal
interrupt handler.
- The 'enable' interrupts functions for RPS and GuC logs, as a measure
of precaution. Here we could relax a bit and don't check GT INT DW
at all or, if we do, at least we should clear the offending bit
(which is what this patch does).
Note that, if every bit is cleared on reading GT INT DW, the register
won't be locked. Also note that, according to the BSpec, GT INT DW
cannot be cleared without first servicing the Selector & Shared IIR
registers.
v2:
- Remove some code duplication (Tvrtko)
- Make sure GT_INTR_DW are protected by the irq spinlock, since it's a
global resource (Tvrtko)
v3: Optimize the spinlock (Tvrtko)
v4: Rebase.
v5:
- take spinlock on outer scope to please sparse (Mika)
- use raw_reg accessors (Mika)
v6: omit the continue in looping banks (Michel)
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> (v4)
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180406093237.14548-1-mika.kuoppala@linux.intel.com
Not all callers want the GPU error to handled in the same way, so expose
a control parameter. In the first instance, some callers do not want the
heavyweight error capture so add a bit to request the state to be
captured and saved.
v2: Pass msg down to i915_reset/i915_reset_engine so that we include the
reason for the reset in the dev_notice(), superseding the earlier option
to not print that notice.
v3: Stash the reason inside the i915->gpu_error to handover to the direct
reset from the blocking waiter.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jeff McGee <jeff.mcgee@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180320100449.1360-2-chris@chris-wilson.co.uk
Originally we were inlining gen8_cs_irq_handler() and so expected the
compiler to constant-fold away the irq_shift (so we had hardcoded it as
opposed to use engine->irq_shift). However, we dropped the inline given
the proliferation of gen8_cs_irq_handler()s. If we pull the shifting
of the iir into the caller, we can shrink the code still further:
add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-34 (-34)
Function old new delta
gen8_cs_irq_handler 123 118 -5
gen8_gt_irq_handler 261 248 -13
gen11_irq_handler 722 706 -16
v2: Drop gen11_cs_irq_handler now that it is a simple
stub around gen8_cs_irq_handler (Daniele)
References: 5d3d69d5c1 ("drm/i915: Stop inlining the execlists IRQ handler")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180309010808.11921-1-chris@chris-wilson.co.uk
v2: Rebase.
v3:
* Remove DPF, it has been removed from SKL+.
* Fix -internal rebase wrt. execlists interrupt handling.
v4: Rebase.
v5:
* Updated for POR changes. (Daniele Ceraolo Spurio)
* Merged with irq handling fixes by Daniele Ceraolo Spurio:
* Simplify the code by using gen8_cs_irq_handler.
* Fix interrupt handling for the upstream kernel.
v6:
* Remove early bringup debug messages (Tvrtko)
* Add NB about arbitrary spin wait timeout (Tvrtko)
v7 (from Paulo):
* Don't try to write RO bits to registers.
* Don't check for PCH types that don't exist. PCH interrupts are not
here yet.
v9:
* squashed in selector and shared register handling (Daniele)
* skip writing of irq if data is not valid (Daniele)
* use time_after32 (Chris)
* use I915_MAX_VCS and I915_MAX_VECS (Daniele)
* remove fake pm interrupt handling for later patch (Mika)
v10:
* Direct processing of banks. clear banks early (Chris)
* remove poll on valid bit, only clear valid bit (Mika)
* use raw accessors, better naming (Chris)
v11:
* adapt to raw_reg_[read|write]
* bring back polling the valid bit (Daniele)
v12:
* continue if unset intr_dw (Daniele)
* comment the usage of gen8_de_irq_handler bits (Daniele)
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180228101153.7224-2-mika.kuoppala@linux.intel.com
The compiler is not automatically caching the i915->regs address inside
a register and emitting a load for every mmio access. For simple
functions like gen8_gt_irq_handler that are already using the raw
accessors, we can open-code them for substantial savings:
add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-83 (-83)
Function old new delta
gen8_gt_irq_handler 290 266 -24
gen8_gt_irq_ack 181 122 -59
Total: Before=954637, After=954554, chg -0.01%
v2: Add raw_reg_read/raw_reg_write.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180219100926.16554-1-chris@chris-wilson.co.uk
The frame counter may have got reset between disabling and enabling vblank
interrupts due to DMC putting the hardware to DC5/6 states if PSR was
active. The frame counter could also have stalled if PSR was active in case
there was no DMC. The frame counter resetting has a user visible impact
of screen freezes.
Make use of drm_vblank_restore() to compute missed vblanks for the duration
in which vblank interrupts were disabled and update the vblank counter with
this value as diff. There's no need to check if PSR was actually active in
the interrupt disabled duration, so simplify the check to a feature check.
Enabling vblank interrupts wakes up the hardware from DC5/6 and prevents it
from going back again as long as the there are pending interrupts. So, we
don't have to explicity disallow DC5/6 after enabling vblank interrupts to
keep the counter running.
This change is not applicable to CHV, as enabling interrupts does not
prevent the hardware from activating PSR.
v2: Added comments(Rodrigo) and rewrote commit message.
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180203051302.9974-10-dhinakaran.pandiyan@intel.com
On some Cannonlake SKUs we have a dedicated Aux for port F,
that is only the full split between port A and port E.
There is still no Aux E for Port E, as in previous platforms,
because port_E still means shared lanes with port A.
v2: Rebase.
v3: Add couple missed PORT_F cases on intel_dp.
v4: Rebase and fix commit message.
v5: Squash Imre's "drm/i915: Add missing AUX_F power well string"
v6: Rebase on top of display headers rework.
v7: s/IS_CANNONLAKE/IS_CNL_WITH_PORT_F (DK)
v8: Fix Aux bits for Port F (DK)
v9: Fix VBT definition of Port F (DK).
v10: Squash power well addition to this patch to avoid
warns as pointed by DK.
v11: Clean up squashed commit message. (David)
v12: Remove unnecessary handling for older platforms (DK)
Adding AUX_F to PG2 following other existent ones. (DK)
Cc: David Weinehall <david.weinehall@linux.intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: David Weinehall <david.weinehall@linux.intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180129232223.766-2-rodrigo.vivi@intel.com
The execlists emulation on top of the GuC (used for scheduling and
preemption) depends on the MI_USER_INTERRUPT for its notifications and
tasklet action. As we always employ the irq, there is no advantage in
ever disabling it while we are using the GuC, so allow us to arm the
breadcrumb irq when enabling GuC submission and disarm upon disabling.
The impact should be lessened by the delayed irq disabling we do (we
only disable after receiving an interrupt for which no one was wanting),
but allowing guc to explicitly manage the irq in relation to itself is
simpler and prevents an issue with losing an interrupt for preemption
as it is not coupled to an active request.
Internally, we add a reference counter (breadcrumbs.irq_enabled) as a
simple mechanism to allow GuC to keep the breadcrumb irq enabled. To
improve upon always enabling the irq while guc is selected, we need
to hook into the parking facility of intel_engines so that we only enable
the breadcrumbs while the GT is active (one step better would be to
individually park/unpark each engine).
In effect, this means that we keep the breadcrumb irq always enabled for
the entire duration the guc is busy, whereas before we would try to
switch it off whenever we idled for more than interrupt with no
associated waiters. The difference *should* be negligible in practice!
v2: Stop abusing fence signaling (and its auxiliary data structures) to
enable the breadcrumbs irqs.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>,
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>,
Link: https://patchwork.freedesktop.org/patch/msgid/20171025143943.7661-3-chris@chris-wilson.co.uk
Back in commit a4b2b01523 ("drm/i915: Don't mark an execlists
context-switch when idle") we noticed the presence of late
context-switch interrupts. We were able to filter those out by looking
at whether the ELSP remained active, but in commit beecec9017
("drm/i915/execlists: Preemption!") that became problematic as we now
anticipate receiving a context-switch event for preemption while ELSP
may be empty. To restore the spurious interrupt suppression, add a
counter for the expected number of pending context-switches and skip if
we do not need to handle this interrupt to make forward progress.
v2: Don't forget to switch on for preempt.
v3: Reduce the counter to a on/off boolean tracker. Declare the HW as
active when we first submit, and idle after the final completion event
(with which we confirm the HW says it is idle), and track each source
of activity separately. With a finite number of sources, it should aide
us in debugging which gets stuck.
Fixes: beecec9017 ("drm/i915/execlists: Preemption!")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171023213237.26536-3-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
When we write to ELSP, it triggers a context preemption at the earliest
arbitration point (3DPRIMITIVE, some PIPECONTROLs, a few other
operations and the explicit MI_ARB_CHECK). If this is to the same
context, it triggers a LITE_RESTORE where the RING_TAIL is merely
updated (used currently to chain requests from the same context
together, avoiding bubbles). However, if it is to a different context, a
full context-switch is performed and it will start to execute the new
context saving the image of the old for later execution.
Previously we avoided preemption by only submitting a new context when
the old was idle. But now we wish embrace it, and if the new request has
a higher priority than the currently executing request, we write to the
ELSP regardless, thus triggering preemption, but we tell the GPU to
switch to our special preemption context (not the target). In the
context-switch interrupt handler, we know that the previous contexts
have finished execution and so can unwind all the incomplete requests
and compute the new highest priority request to execute.
It would be feasible to avoid the switch-to-idle intermediate by
programming the ELSP with the target context. The difficulty is in
tracking which request that should be whilst maintaining the dependency
change, the error comes in with coalesced requests. As we only track the
most recent request and its priority, we may run into the issue of being
tricked in preempting a high priority request that was followed by a
low priority request from the same context (e.g. for PI); worse still
that earlier request may be our own dependency and the order then broken
by preemption. By injecting the switch-to-idle and then recomputing the
priority queue, we avoid the issue with tracking in-flight coalesced
requests. Having tried the preempt-to-busy approach, and failed to find
a way around the coalesced priority issue, Michal's original proposal to
inject an idle context (based on handling GuC preemption) succeeds.
The current heuristic for deciding when to preempt are only if the new
request is of higher priority, and has the privileged priority of
greater than 0. Note that the scheduler remains unfair!
v2: Disable for gen8 (bdw/bsw) as we need additional w/a for GPGPU.
Since, the feature is now conditional and not always available when we
have a scheduler, make it known via the HAS_SCHEDULER GETPARAM (now a
capability mask).
v3: Stylistic tweaks.
v4: Appease Joonas with a snippet of kerneldoc, only to fuel to fire of
the preempt vs preempting debate.
Suggested-by: Michal Winiarski <michal.winiarski@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171003203453.15692-8-chris@chris-wilson.co.uk
One of the differences I spotted for GEN8+ platforms when
compared to older platforms is that spec for BDW+ includes
this sentence:
"The first CRC done indication after CRC is first enabled is
from only a partial frame, so it will not have the expected
CRC result."
This is an indication that on BDW+ platforms, by the time
we receive the interrupt the CRC is not accurate yet for
the full frame. That would be ok, because we are already
skipping the first CRC for all platforms. However the comment
on the code state that it is for some unknown reason. Also,
on CHV (gen8 lp) we were already discarding the second CRC
as well to make sure we have a reliable CRC on hand.
So based on all ou tests and bugs it seems that it is not
on CHV that needs to discard 2 first CRCs, but all BDW+
platforms.
Starting on SKL we have this CRC done bit (24), but the
experiments around the use of this bit wasn't that stable
as just discarding the second CRC. So, let's for now
just move with CHV solution for all gen8+ platforms and
make our CI a bit more stable.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102374
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101309
Cc: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Tested-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170928002040.7917-1-rodrigo.vivi@intel.com
For certain platforms on certain encoders, timings are driven
from port instead of pipe. Thus, we can't rely on pipe scanline
registers to get the timing information. Some cases scanline
register read will not be functional.
This is causing vblank evasion logic to fail since it relies on
scanline, causing atomic update failure warnings.
This patch uses pipe framestamp and current timestamp registers
to calculate scanline. This is an indirect way to get the scanline.
It helps resolve atomic update failure for gen9 dsi platforms.
v2: Addressed Ville and Daniel's review comments. Updated the
register MACROs, handled race condition for register reads,
extracted timings from the hwmode. Removed the dependency on
crtc->config to get the encoder type.
v3: Made get scanline function generic
v4: Addressed Ville's review comments. Added a flag to decide timestamp
based scanline reporting. Changed 64bit variables to u32
v5: Adressed Ville's review comments. Put the scanline compute function
at the place of caller. Removed hwmode flags from uapi and used a local
i915 data structure instead.
v6: Used vblank hwmode to get the timings.
v7: Fixed sparse warnings, indentation and minor review comments.
v8: Limited this only for Gen9 DSI.
Credits-to: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Chandra Konduru <chandra.konduru@intel.com>
Signed-off-by: Vidya Srinivas <vidya.srinivas@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1506347761-4201-1-git-send-email-vidya.srinivas@intel.com
i830 seems to occasionally forget the PIPESTAT enable bits when
we read the register. These aren't the only registers on i830 that
have problems with RMW, as reading the double buffered plane
registers returns the latched value rather than the last written
value. So something similar is perhaps going on with PIPESTAT.
This corruption results on vblank interrupts occasionally turning off
on their own, which leads to vblank timeouts and generally a stuck
display subsystem.
So let's not RMW the pipestat enable bits, and instead use the cached
copy we have around.
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170914151731.5034-1-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>
"CNL PCH chance of hang when software accesses south display
registers after hotplug is enabled.
Workaround: Program 0xC2000 bits 11:8 = 0xF before enabling
south display hotplug detection."
"Workaround only needs to be applied to pre-production steppings
used in graphics capable SKUs, but it is easier to apply to
everything, and does not hurt."
v2: Moving from clock gating to right before enabling
SHOTPLUG_CTL as it should be.
v3: Align with SOUTH_CHICKEN1 (DK) and consequently use proper
spaces on bits definition since other bits around already use
new style. And now that checkpatch is not noise anymore I also
fixed the reg read mask to avoid going over 80 chars.
Suggested-by: Ben Widawsky <ben@bwidawsk.net>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170919215703.25947-1-rodrigo.vivi@intel.com
Currently we're unmasking some random looking bits in HWSTAM
on gen3/4/5. The two bits we apparently unmask are 0 and 12,
and also bits 16-31 on gen4/5.
What those bits do depends on the gen as follows:
bit 0: Breakpoint (gen2), ASLE (gen3), reserved (gen4), render user interrupt (gen5)
bit 12: Sync flush statusa (gen2-4), reserved (gen5)
bit 16-31: The ones that can unmasked seem to be mostly some
display stuff on gen4. Bit 18 is the PIPE_CONTROL notify,
which might be the only intresting one. On gen5 all the
bits are reserved.
So I don't know whether we actually depend on that status page write
somehow. Extra seqno coherency by accident perhaps? Except we don't
even unmask the user interrupt bit in HWSTAM except on gen5, and
sync flush isn't something we use normally, so seems unlikely. So
let's just assume we don't need any of this and mask everything in
HWSTAM.
From gen6 onwards there's a separate HWSTAM for each engine, and so
we deal with them during the engine setup.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170818183705.27850-15-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Bspec claims that HWSTAM is only 16 bits on gen3, but the other
interrupts registers are 32 bits and there are 18 valid interrupt
bits. Hence a 16 bit HWSTAM wouldn't be able to contain all the
bits, so it seems the spec is incorrect about the size of the
register. And indeed I can clear bits 16 and 17 just fine with
a 32 bit write. So let's adjust the code to treat the register
as 32 bits.
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170818183705.27850-14-ville.syrjala@linux.intel.com
Eliminate the loops from the gen2-3 irq handlers. Since we don't use
MSI anymore on these platforms, and thus the CPU interrupt will be level
triggered, we shouldn't need to play any tricks with IER to induce edges
from IIR. IIR itself still detects only edges from PIPESTAT & co. on
gen4 but since IIR is double buffered and we only clear one bit per irq
handler invocation we can use the normal "clear PIPESTAT & co. -> clear
IIR" approach to ack the interrupts. On gen2 everything is level
triggered, and gen3 presumably follows either the gen2 or gen4 approach
since nothing else would really make sense.
v2: Drop the IER tricks since we no longer use MSI
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170818183705.27850-12-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
