0f36a85c3b
After resetting the GPU (or subset of engines), call synchronize_irq()
to flush any pending irq before proceeding with the cleanup. For a
device level reset, we disable the interupts around the reset, but when
resetting just one engine, we have to avoid such global disabling. This
leaves us open to an interrupt arriving for the engine as we try to
reset it. We already do try to flush the IIR following the reset, but we
have to ensure that the in-flight interrupt does not land after we start
cleaning up after the reset; enter synchronize_irq().
As it current stands, we very rarely, but fatally, see sequences such as:
2.... 57964564us : execlists_reset_prepare: rcs0
2.... 57964613us : execlists_reset: rcs0 seqno=424
0d.h1 57964615us : gen8_cs_irq_handler: rcs0 CS active=1
2d..1 57964617us : __i915_request_unsubmit: rcs0 fence 29:1056 <- global_seqno 1060
2.... 57964703us : execlists_reset_finish: rcs0
0..s. 57964705us : execlists_submission_tasklet: rcs0 awake?=1, active=0, irq-posted?=1
v2: Move the sync into the execlists reset handler so that we coordinate
the flush with disabling the interrupt handling and canceling the
pending interrupt.
v3: Just use synchronize_hardirq() to avoid the might_sleep(), we do not
yet have threaded-irq to worry about.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Jeff McGee <jeff.mcgee@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180322073533.5313-4-chris@chris-wilson.co.uk
Reviewed-by: Jeff McGee <jeff.mcgee@intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.