Re: [PATCH] drm/amd/display: replace use of msleep(<20) with usleep_range for better accuracy

Shuah Khan
2025-03-28T22:46:02Z

On 3/26/25 01:00, James Flowers wrote:
> msleep < 20ms will often sleep for ~20ms (according to Documentation/timers/timers-howto.rst).

Can you elaborate and explain why this change is necessary?

>
> Signed-off-by: James Flowers <bold.zone2373@fastmail.com>
> ---
> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> index 2cd35392e2da..2d225735602b 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> @@ -682,7 +682,7 @@ static bool execute_synaptics_rc_command(struct drm_dp_aux *aux,
> if (rc_cmd == cmd)
> // active is 0
> break;
> - msleep(10);
> + usleep_range(10000, 10200);
> }
>
> // read rc result

thanks,
-- Shuah