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authorJesse Barnes <jbarnes@virtuousgeek.org>2011-08-01 15:02:20 -0700
committerKeith Packard <keithp@keithp.com>2011-08-01 15:24:18 -0700
commit11bee43ebba0bfc92165c059f6e9869197ea8889 (patch)
tree6bc213dfd279525f0400524ac31641ed8fa7e172 /drivers/gpu
parentcda2bb78c24de7674eafa3210314dc75bed344a6 (diff)
drm/i915/dp: wait for previous AUX channel activity to clear
Before initiating a new read or write on the DP AUX channel, wait for any outstanding activity to complete. This may happen during normal retry behavior. If the wait fails (i.e. after 1ms the AUX channel is still busy) dump a backtrace to make the caller easier to spot. v2: use msleep instead, and timeout after 3ms (only ever saw 1 retry with msleep in testing) v3: fix backtrace check to trigger if the 3ms wait times out Fixes https://bugs.freedesktop.org/show_bug.cgi?id=38136. Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> Reviewed-by: Keith Packard <keithp@keithp.com> Signed-off-by: Keith Packard <keithp@keithp.com>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/i915/intel_dp.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 449364187bc0..ba72fbcbbbc9 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -315,9 +315,17 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
else
precharge = 5;
- if (I915_READ(ch_ctl) & DP_AUX_CH_CTL_SEND_BUSY) {
- DRM_ERROR("dp_aux_ch not started status 0x%08x\n",
- I915_READ(ch_ctl));
+ /* Try to wait for any previous AUX channel activity */
+ for (try = 0; try < 3; try++) {
+ status = I915_READ(ch_ctl);
+ if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0)
+ break;
+ msleep(1);
+ }
+
+ if (try == 3) {
+ WARN(1, "dp_aux_ch not started status 0x%08x\n",
+ I915_READ(ch_ctl));
return -EBUSY;
}