[AMD Official Use Only - Internal Distribution Only]
On Wed, Sep 16, 2020 at 3:42 PM Qingqing Zhuo <qingqing.zhuo@xxxxxxx> wrote:
>
> From: jinlong zhang <jinlong.zhang@xxxxxxx>
>
> [why]
> while read edid return defer, then it enter to msleep, but it actually
> took more time during msleep, this will cause remaining edid read
> fail.
>
> [how]
> Replacing msleep with udelay, it will not take any extra time, edid return pass finally.
How long of a delay are we talking about here? Some platforms don't support long udelays and someone will send a patch to change this to msleep.
Alex
---------------------
Hi Alex,
It's between 0-5ms for generic cases, though there exist some dongle workaround cases where we will do 70ms. Would this be a concern?
Thank you,
Lillian
>
> Signed-off-by: jinlong zhang <jinlong.zhang@xxxxxxx>
> Reviewed-by: Wenjing Liu <Wenjing.Liu@xxxxxxx>
> Acked-by: Qingqing Zhuo <qingqing.zhuo@xxxxxxx>
> ---
> drivers/gpu/drm/amd/display/dc/dce/dce_aux.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
> b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
> index 743042d5905a..cdcad82765e0 100644
> --- a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
> +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
> @@ -653,7 +653,7 @@ bool dce_aux_transfer_with_retries(struct ddc_service *ddc,
> if ((*payload->reply == AUX_TRANSACTION_REPLY_AUX_DEFER) ||
> (*payload->reply == AUX_TRANSACTION_REPLY_I2C_OVER_AUX_DEFER)) {
> if (payload->defer_delay > 0)
> - msleep(payload->defer_delay);
> +
> + udelay(payload->defer_delay * 1000);
> }
> }
> break;
> --
> 2.17.1
>
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