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From:   Amit Pundir <amit.pundir@linaro.org>
Date:   Wed, 2 Aug 2023 14:45:59 +0530
Message-ID: <CAMi1Hd31A53-87EdnupZio_FCjgMRyPRxvsfzeY=q-iT=3qBfA@mail.gmail.com>
Subject: Re: [PATCH] Revert "drm/bridge: lt9611: Do not generate HFP/HBP/HSA
 and EOT packet"
To:     Neil Armstrong <neil.armstrong@linaro.org>
Cc:     Andrzej Hajda <andrzej.hajda@intel.com>,
        Robert Foss <rfoss@kernel.org>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>, Marek Vasut <marex@denx.de>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        Jagan Teki <jagan@amarulasolutions.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>
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Precedence: bulk

On Wed, 2 Aug 2023 at 14:22, Neil Armstrong <neil.armstrong@linaro.org> wrote:
>
> This reverts commit [1] to fix display regression on the Dragonboard 845c
> (SDM845) devboard.

Tested-by: Amit Pundir <amit.pundir@linaro.org>

Regards,
Amit Pundir

>
> There's a mismatch on the real action of the following flags:
> - MIPI_DSI_MODE_VIDEO_NO_HSA
> - MIPI_DSI_MODE_VIDEO_NO_HFP
> - MIPI_DSI_MODE_VIDEO_NO_HBP
> which leads to a non-working display on qcom platforms.
>
> [1] 8ddce13ae696 ("drm/bridge: lt9611: Do not generate HFP/HBP/HSA and EOT packet")
>
> Cc: Marek Vasut <marex@denx.de>
> Cc: Robert Foss <rfoss@kernel.org>
> Cc: Jagan Teki <jagan@amarulasolutions.com>
> Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
> Fixes: 8ddce13ae69 ("drm/bridge: lt9611: Do not generate HFP/HBP/HSA and EOT packet")
> Reported-by: Amit Pundir <amit.pundir@linaro.org>
> Link: https://lore.kernel.org/r/CAMi1Hd0TD=2z_=bcDrht3H_wiLvAFcv8Z-U_r_KUOoeMc6UMjw@mail.gmail.com/
> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
> ---
>  drivers/gpu/drm/bridge/lontium-lt9611.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/lontium-lt9611.c b/drivers/gpu/drm/bridge/lontium-lt9611.c
> index 5163e5224aad..9663601ce098 100644
> --- a/drivers/gpu/drm/bridge/lontium-lt9611.c
> +++ b/drivers/gpu/drm/bridge/lontium-lt9611.c
> @@ -774,9 +774,7 @@ static struct mipi_dsi_device *lt9611_attach_dsi(struct lt9611 *lt9611,
>         dsi->lanes = 4;
>         dsi->format = MIPI_DSI_FMT_RGB888;
>         dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
> -                         MIPI_DSI_MODE_VIDEO_HSE | MIPI_DSI_MODE_VIDEO_NO_HSA |
> -                         MIPI_DSI_MODE_VIDEO_NO_HFP | MIPI_DSI_MODE_VIDEO_NO_HBP |
> -                         MIPI_DSI_MODE_NO_EOT_PACKET;
> +                         MIPI_DSI_MODE_VIDEO_HSE;
>
>         ret = devm_mipi_dsi_attach(dev, dsi);
>         if (ret < 0) {
>
> ---
> base-commit: f590814603bf2dd8620584b7d59ae94d7c186c69
> change-id: 20230802-revert-do-not-generate-hfp-hbp-hsa-eot-packet-6f042b1ba813
>
> Best regards,
> --
> Neil Armstrong <neil.armstrong@linaro.org>
>