[PATCH 1/2] drm/amdgpu/display: adjust msleep limit in dp_wait_for_training_aux_rd_interval

[Chen, Guchun]

[Public]

Series is: Reviewed-by: Guchun Chen guchun.chen at amd.com<mailto:guchun.chen at amd.com>

Regards,
Guchun

From: Deucher, Alexander <Alexander.Deucher at amd.com>
Sent: Saturday, January 22, 2022 1:00 AM
To: Chen, Guchun <Guchun.Chen at amd.com>; amd-gfx at lists.freedesktop.org
Subject: Re: [PATCH 1/2] drm/amdgpu/display: adjust msleep limit in dp_wait_for_training_aux_rd_interval


[Public]

It just changes the limit for when we use msleep vs udelay, not the units.

Alex
________________________________
From: Chen, Guchun <Guchun.Chen at amd.com<mailto:Guchun.Chen at amd.com>>
Sent: Thursday, January 20, 2022 8:49 PM
To: Deucher, Alexander <Alexander.Deucher at amd.com<mailto:Alexander.Deucher at amd.com>>; amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org> <amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>>
Cc: Deucher, Alexander <Alexander.Deucher at amd.com<mailto:Alexander.Deucher at amd.com>>
Subject: RE: [PATCH 1/2] drm/amdgpu/display: adjust msleep limit in dp_wait_for_training_aux_rd_interval

[Public]

If we change if condition, how about the division by "wait_in_micro_secs/1000", as the sleep time is less now. Shall we adjust it as well?

Regards,
Guchun

-----Original Message-----
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org<mailto:amd-gfx-bounces at lists.freedesktop.org>> On Behalf Of Alex Deucher
Sent: Friday, January 21, 2022 2:04 AM
To: amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>
Cc: Deucher, Alexander <Alexander.Deucher at amd.com<mailto:Alexander.Deucher at amd.com>>
Subject: [PATCH 1/2] drm/amdgpu/display: adjust msleep limit in dp_wait_for_training_aux_rd_interval

Some architectures (e.g., ARM) have relatively low udelay limits.
On most architectures, anything longer than 2000us is not recommended.
Change the check to align with other similar checks in DC.

Signed-off-by: Alex Deucher <alexander.deucher at amd.com<mailto:alexander.deucher at amd.com>>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index 1f8831156bc4..aa1c67c3c386 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -202,7 +202,7 @@ void dp_wait_for_training_aux_rd_interval(
         uint32_t wait_in_micro_secs)
 {
 #if defined(CONFIG_DRM_AMD_DC_DCN)
-       if (wait_in_micro_secs > 16000)
+       if (wait_in_micro_secs > 1000)
                 msleep(wait_in_micro_secs/1000);
         else
                 udelay(wait_in_micro_secs);
--
2.34.1
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