Re: [PATCH][RESEND] drm/bridge: ti-sn65dsi83: Check link status register after enabling the bridge

[Robert Foss <robert.foss@linaro.org>]

On Sun, 13 Feb 2022 at 03:27, Marek Vasut <marex@denx.de> wrote:
>
> In rare cases, the bridge may not start up correctly, which usually
> leads to no display output. In case this happens, warn about it in
> the kernel log.
>
> Signed-off-by: Marek Vasut <marex@denx.de>
> Cc: Jagan Teki <jagan@amarulasolutions.com>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Robert Foss <robert.foss@linaro.org>
> Cc: Sam Ravnborg <sam@ravnborg.org>
> Cc: dri-devel@lists.freedesktop.org
> ---
>  drivers/gpu/drm/bridge/ti-sn65dsi83.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
> index 19daaddd29a41..1d7c154ea1d79 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
> @@ -488,6 +488,11 @@ static void sn65dsi83_atomic_enable(struct drm_bridge *bridge,
>         /* Clear all errors that got asserted during initialization. */
>         regmap_read(ctx->regmap, REG_IRQ_STAT, &pval);
>         regmap_write(ctx->regmap, REG_IRQ_STAT, pval);
> +
> +       usleep_range(10000, 12000);
> +       regmap_read(ctx->regmap, REG_IRQ_STAT, &pval);
> +       if (pval)
> +               dev_err(ctx->dev, "Unexpected link status 0x%02x\n", pval);
>  }
>
>  static void sn65dsi83_atomic_disable(struct drm_bridge *bridge,
> --
> 2.34.1
>

Reviewed-by: Robert Foss <robert.foss@linaro.org>