As we've unfortunately started to come to expect from PSR on Intel
platforms, PSR2 selective fetch is not at all ready to be enabled on
Tigerlake as it results in severe flickering issues - at least on this
ThinkPad X1 Carbon 9th generation. The easiest way I've found of
reproducing these issues is to just move the cursor around the left border
of the screen (suspicious…).
So, fix people's displays again and turn PSR2 selective fetch off for all
steppings of Tigerlake. This can be re-enabled again if someone from Intel
finds the time to fix this functionality on OEM machines.
Signed-off-by: Lyude Paul <lyude(a)redhat.com>
Fixes: 7f6002e58025 ("drm/i915/display: Enable PSR2 selective fetch by default")
Cc: Gwan-gyeong Mun <gwan-gyeong.mun(a)intel.com>
Cc: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Cc: José Roberto de Souza <jose.souza(a)intel.com>
Cc: Jani Nikula <jani.nikula(a)linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi(a)intel.com>
Cc: intel-gfx(a)lists.freedesktop.org
Cc: <stable(a)vger.kernel.org> # v5.16+
---
drivers/gpu/drm/i915/display/intel_psr.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index a1a663f362e7..25c16abcd9cd 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -737,10 +737,14 @@ static bool intel_psr2_sel_fetch_config_valid(struct intel_dp *intel_dp,
return false;
}
- /* Wa_14010254185 Wa_14010103792 */
- if (IS_TGL_DISPLAY_STEP(dev_priv, STEP_A0, STEP_C0)) {
+ /*
+ * There's two things stopping this from being enabled on TGL:
+ * For steps A0-C0: workarounds Wa_14010254185 Wa_14010103792 are missing
+ * For all steps: PSR2 selective fetch causes screen flickering
+ */
+ if (IS_TIGERLAKE(dev_priv)) {
drm_dbg_kms(&dev_priv->drm,
- "PSR2 sel fetch not enabled, missing the implementation of WAs\n");
+ "PSR2 sel fetch not enabled, currently broken on TGL\n");
return false;
}
--
2.34.1
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From f524d9c95fab54783d0038f7a3e8c014d5b56857 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer(a)redhat.com>
Date: Fri, 28 Jan 2022 10:58:40 -0500
Subject: [PATCH] dm: revert partial fix for redundant bio-based IO accounting
Reverts a1e1cb72d9649 ("dm: fix redundant IO accounting for bios that
need splitting") because it was too narrow in scope (only addressed
redundant 'sectors[]' accounting and not ios, nsecs[], etc).
Cc: stable(a)vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer(a)redhat.com>
Link: https://lore.kernel.org/r/20220128155841.39644-3-snitzer@redhat.com
Signed-off-by: Jens Axboe <axboe(a)kernel.dk>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index c0ae8087c602..9849114b3c08 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1442,9 +1442,6 @@ static void init_clone_info(struct clone_info *ci, struct mapped_device *md,
ci->sector = bio->bi_iter.bi_sector;
}
-#define __dm_part_stat_sub(part, field, subnd) \
- (part_stat_get(part, field) -= (subnd))
-
/*
* Entry point to split a bio into clones and submit them to the targets.
*/
@@ -1480,18 +1477,6 @@ static void __split_and_process_bio(struct mapped_device *md,
GFP_NOIO, &md->queue->bio_split);
ci.io->orig_bio = b;
- /*
- * Adjust IO stats for each split, otherwise upon queue
- * reentry there will be redundant IO accounting.
- * NOTE: this is a stop-gap fix, a proper fix involves
- * significant refactoring of DM core's bio splitting
- * (by eliminating DM's splitting and just using bio_split)
- */
- part_stat_lock();
- __dm_part_stat_sub(dm_disk(md)->part0,
- sectors[op_stat_group(bio_op(bio))], ci.sector_count);
- part_stat_unlock();
-
bio_chain(b, bio);
trace_block_split(b, bio->bi_iter.bi_sector);
submit_bio_noacct(bio);