On 2022-12-14 13:48, Alex Deucher wrote:
On Wed, Dec 14, 2022 at 3:22 PM Aurabindo Pillai
<aurabindo.pillai@xxxxxxx> wrote:
From: Alex Hung <alex.hung@xxxxxxx>
[Why]
When running IGT kms_bw test with DP monitor, some systems crash from
msleep no matter how long or short the time is.
[How]
To replace msleep with mdelay.
Can you provide a bit more info about the crash? A lot of platforms
don't support delay larger than 2-4ms so this change will generate
errors on ARM and possibly other platforms.
Alex
The msleep was introduced in eec3303de3378 for non-compliant display
port monitors but IGT's kms_bw test can cause a recent h/w to hang at
msleep(60) when calling "igt_remove_fb" in IGT
(https://gitlab.freedesktop.org/drm/igt-gpu-tools/-/blob/master/tests/kms_bw.c#L197)
It is possible to workaround this by reversing order of
igt_remove_fb(&buffer[i]), as the following example:
igt_create_color_fb with the order buffer[0], buffer[1], buffer[2]
Hangs:
igt_remove_fb with the order buffer[0], buffer[1], buffer[2]
No hangs:
igt_remove_fb with the reversed order buffer[2], buffer[1], buffer[0]
However, IGT simply exposes the problem and it makes more sense to stop
the hang from occurring.
I also tried to remove the msleep completely and it also work, but I
didn't want to break the fix for the original problematic hardware
configuration.
Acked-by: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
Signed-off-by: Alex Hung <alex.hung@xxxxxxx>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
---
drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
index 913a1fe6b3da..e6251ccadb70 100644
--- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
@@ -1215,7 +1215,7 @@ void dce110_blank_stream(struct pipe_ctx *pipe_ctx)
* After output is idle pattern some sinks need time to recognize the stream
* has changed or they enter protection state and hang.
*/
- msleep(60);
+ mdelay(60);
} else if (pipe_ctx->stream->signal == SIGNAL_TYPE_EDP) {
if (!link->dc->config.edp_no_power_sequencing) {
/*
--
2.39.0
