linux-kernel - Re: [PATCH] drm/bridge: ps8640: Use constant sleep time for polling hpd

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Message-ID: <CAN6tsi4i+3H4-e7wCGTrpR+RCZy4OfgErn3bFmOWtWRkZy_whg@mail.gmail.com>
Date:   Fri, 31 Mar 2023 10:48:29 +0200
From:   Robert Foss <rfoss@...nel.org>
To:     Pin-yen Lin <treapking@...omium.org>
Cc:     Douglas Anderson <dianders@...omium.org>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH] drm/bridge: ps8640: Use constant sleep time for polling hpd

On Fri, Mar 31, 2023 at 5:02 AM Pin-yen Lin <treapking@...omium.org> wrote:
>
> The default hpd_wait_us in panel_edp.c is 2 seconds. This makes the
> sleep time in the polling of _ps8640_wait_hpd_asserted become 200ms.
> Change it to a constant 20ms to speed up the function.
>
> Signed-off-by: Pin-yen Lin <treapking@...omium.org>
> ---
>
>  drivers/gpu/drm/bridge/parade-ps8640.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
> index b823e55650b1..c3eb45179405 100644
> --- a/drivers/gpu/drm/bridge/parade-ps8640.c
> +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
> @@ -184,7 +184,7 @@ static int _ps8640_wait_hpd_asserted(struct ps8640 *ps_bridge, unsigned long wai
>          * actually connected to GPIO9).
>          */
>         ret = regmap_read_poll_timeout(map, PAGE2_GPIO_H, status,
> -                                      status & PS_GPIO9, wait_us / 10, wait_us);
> +                                      status & PS_GPIO9, 20000, wait_us);
>
>         /*
>          * The first time we see HPD go high after a reset we delay an extra
> --
> 2.40.0.348.gf938b09366-goog
>

Snoozing for a few days before applying.

Reviewed-by: Robert Foss <rfoss@...nel.org>