From 8007cff80dc7b5b53ccb6f21f67f79858a723a29 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Mon, 7 Feb 2022 15:26:59 +0200
Subject: drm/i915: Fix dbuf slice config lookup
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Alt-commit: a28fde308c3c1c174249ff9559b57f24e6850086
Git-commit: 698bef8ff5d2edea5d1c9d6e5adf1bfed1e8a106
Patch-mainline: v5.17-rc5
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
Apparently I totally fumbled the loop condition when I
removed the ARRAY_SIZE() stuff from the dbuf slice config
lookup. Comparing the loop index with the active_pipes bitmask
is utter nonsense, what we want to do is check to see if the
mask is zero or not.
Note that the code actually ended up working correctly despite
the fumble, up until commit eef173954432 ("drm/i915: Allow
!join_mbus cases for adlp+ dbuf configuration") when things
broke for real.
Cc: stable@vger.kernel.org
Fixes: 05e8155afe35 ("drm/i915: Use a sentinel to terminate the dbuf slice arrays")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220207132700.481-1-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit a28fde308c3c1c174249ff9559b57f24e6850086)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/intel_pm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 3edba7fd0c49..da6ce24a42b2 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4870,7 +4870,7 @@ static u8 compute_dbuf_slices(enum pipe pipe, u8 active_pipes, bool join_mbus,
{
int i;
- for (i = 0; i < dbuf_slices[i].active_pipes; i++) {
+ for (i = 0; dbuf_slices[i].active_pipes != 0; i++) {
if (dbuf_slices[i].active_pipes == active_pipes &&
dbuf_slices[i].join_mbus == join_mbus)
return dbuf_slices[i].dbuf_mask[pipe];
--
2.38.1