This is a note to let you know that I've just added the patch titled
drm/i915: Avoid PPS HW/SW state mismatch due to rounding
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-avoid-pps-hw-sw-state-mismatch-due-to-rounding.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5643205c6340b565a3be0fe0e7305dc4aa551c74 Mon Sep 17 00:00:00 2001
From: Imre Deak <imre.deak@xxxxxxxxx>
Date: Wed, 29 Nov 2017 19:51:37 +0200
Subject: drm/i915: Avoid PPS HW/SW state mismatch due to rounding
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From: Imre Deak <imre.deak@xxxxxxxxx>
commit 5643205c6340b565a3be0fe0e7305dc4aa551c74 upstream.
We store a SW state of the t11_t12 timing in 100usec units but have to
program it in 100msec as required by HW. The rounding used during
programming means there will be a mismatch between the SW and HW states
of this value triggering a "PPS state mismatch" error. Avoid this by
storing the already rounded-up value in the SW state.
Note that we still calculate panel_power_cycle_delay with the finer
100usec granularity to avoid any needless waits using that version of
the delay.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103903
Cc: joks <joks@xxxxxxxx>
Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20171129175137.2889-1-imre.deak@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dp.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -5063,6 +5063,12 @@ intel_dp_init_panel_power_sequencer(stru
*/
final->t8 = 1;
final->t9 = 1;
+
+ /*
+ * HW has only a 100msec granularity for t11_t12 so round it up
+ * accordingly.
+ */
+ final->t11_t12 = roundup(final->t11_t12, 100 * 10);
}
static void
Patches currently in stable-queue which might be from imre.deak@xxxxxxxxx are
queue-4.9/drm-i915-avoid-pps-hw-sw-state-mismatch-due-to-rounding.patch