[PATCH 1/5] drm/xe/rtp: Fix off-by-one when processing rules

Lucas De Marchi lucas.demarchi at intel.com
Thu Jul 25 22:09:52 UTC 2024


Gustavo noticed an odd "+ 2" in rtp_mark_active() while processing
rtp rules and pointed that it should be "+ 1". In fact, while processing
entries without actions (OOB workarounds), if the WA is activated and
has OR rules, it will also inadvertently activate the very next
workaround.

Test in a LNL B0 platform by moving 18024947630 on top of 16020292621,
makes the latter become active:

	$ cat /sys/kernel/debug/dri/0/gt0/workarounds
	...
	OOB Workarounds
		18024947630
		16020292621
		14018094691
		16022287689
		13011645652
		22019338487_display

Fixes: fe19328b900c ("drm/xe/rtp: Add support for entries with no action")
Cc: Gustavo Sousa <gustavo.sousa at intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
---
 drivers/gpu/drm/xe/xe_rtp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_rtp.c b/drivers/gpu/drm/xe/xe_rtp.c
index 02e28274282f..5efe83cc82ab 100644
--- a/drivers/gpu/drm/xe/xe_rtp.c
+++ b/drivers/gpu/drm/xe/xe_rtp.c
@@ -231,7 +231,7 @@ static void rtp_mark_active(struct xe_device *xe,
 	if (first == last)
 		bitmap_set(ctx->active_entries, first, 1);
 	else
-		bitmap_set(ctx->active_entries, first, last - first + 2);
+		bitmap_set(ctx->active_entries, first, last - first + 1);
 }
 
 /**
-- 
2.43.0



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