drm/amd/display: Add a Precise Delay Routine

Fangzhi Zuo · alexdeucher · commit 6c5bb0485810 · 2024-10-22T17:50:38.000-04:00
Fix DP compliance failures 4.2.2.12, 4.3.1.21, 4.9.1.19
caused by imprecise delay on fsleep().

Reviewed-by: Aric Cyr &lt;aric.cyr@amd.com&gt;
Signed-off-by: Fangzhi Zuo &lt;Jerry.Zuo@amd.com&gt;
Signed-off-by: Wayne Lin &lt;wayne.lin@amd.com&gt;
Tested-by: Daniel Wheeler &lt;daniel.wheeler@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c
@@ -272,7 +272,7 @@ void dp_wait_for_training_aux_rd_interval(
 	struct dc_link *link,
 	uint32_t wait_in_micro_secs)
 {
-	fsleep(wait_in_micro_secs);
+	usleep_range_state(wait_in_micro_secs, wait_in_micro_secs, TASK_UNINTERRUPTIBLE);
 
 	DC_LOG_HW_LINK_TRAINING("%s:\n wait = %d\n",
 		__func__,

Original file line number	Diff line number	Diff line change
`@@ -272,7 +272,7 @@ void dp_wait_for_training_aux_rd_interval(`
`272`	`272`	`struct dc_link *link,`
`273`	`273`	`uint32_t wait_in_micro_secs)`
`274`	`274`	`{`
`275`		`- fsleep(wait_in_micro_secs);`
	`275`	`+ usleep_range_state(wait_in_micro_secs, wait_in_micro_secs, TASK_UNINTERRUPTIBLE);`
`276`	`276`
`277`	`277`	`DC_LOG_HW_LINK_TRAINING("%s:\n wait = %d\n",`
`278`	`278`	`__func__,`