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disp: msm: sde: remove idle time from Qsync threshold calculation

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Remove idle time from the Qsync calculation as this was added by
mistake to allow writes to complete just before the next TE but
this causes tearing. Also, to ensure tearing doesn't recur,
round down the threshold lines to the nearest multiple of 4, and
remove a couple of extra lines to compensate for potential
latencies.

Change-Id: I8a53a989e26cbd7f0e2b94caa8df8f5bee3ad26c
Signed-off-by: Steve Cohen <cohens@codeaurora.org>
This commit is contained in:
Steve Cohen
2021-03-24 16:14:46 -04:00
parent 8a3abf2cdf
commit 86d293e6cc
1 changed files with 11 additions and 15 deletions
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26
msm/sde/sde_encoder_phys_cmd.c
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@@ -908,8 +908,6 @@ static int _get_tearcheck_threshold(struct sde_encoder_phys *phys_enc)
u32 default_time_ns;
u32 extra_time_ns;
u32 default_line_time_ns;
u32 idle_time_ns = 0;
u32 transfer_time_us = 0;
if (phys_enc->parent_ops.get_qsync_fps)
phys_enc->parent_ops.get_qsync_fps(
@@ -932,26 +930,24 @@ static int _get_tearcheck_threshold(struct sde_encoder_phys *phys_enc)
/* Calculate the number of extra lines*/
slow_time_ns = DIV_ROUND_UP(1000000000, qsync_min_fps);
default_time_ns = DIV_ROUND_UP(1000000000, default_fps);
sde_encoder_get_transfer_time(phys_enc->parent,
&transfer_time_us);
if (transfer_time_us)
idle_time_ns = default_time_ns -
(1000 * transfer_time_us);
extra_time_ns = slow_time_ns - default_time_ns;
default_line_time_ns = DIV_ROUND_UP(default_time_ns, yres);
extra_time_ns = slow_time_ns - default_time_ns + idle_time_ns;
default_line_time_ns = DIV_ROUND_UP(1000000000, default_fps * yres);
threshold_lines = extra_time_ns / default_line_time_ns;
threshold_lines = DIV_ROUND_UP(extra_time_ns, default_line_time_ns);
/* some DDICs express the timeout value in lines/4, round down to compensate */
threshold_lines = round_down(threshold_lines, 4);
/* remove 2 lines to cover for latency */
if (threshold_lines - 2 > DEFAULT_TEARCHECK_SYNC_THRESH_START)
threshold_lines -= 2;
SDE_DEBUG_CMDENC(cmd_enc, "slow:%d default:%d extra:%d(ns)\n",
slow_time_ns, default_time_ns, extra_time_ns);
SDE_DEBUG_CMDENC(cmd_enc, "xfer:%d(us) idle:%d(ns) lines:%d\n",
transfer_time_us, idle_time_ns, threshold_lines);
SDE_DEBUG_CMDENC(cmd_enc, "min_fps:%d fps:%d yres:%d\n",
qsync_min_fps, default_fps, yres);
SDE_DEBUG_CMDENC(cmd_enc, "min_fps:%d fps:%d yres:%d lines:%d\n",
qsync_min_fps, default_fps, yres, threshold_lines);
SDE_EVT32(qsync_mode, qsync_min_fps, extra_time_ns, default_fps,
yres, transfer_time_us, threshold_lines);
yres, threshold_lines);
}
exit: