Re: [PATCH] drm/panel: visionox-rm69299: Make use of prepare_prev_first

[Doug Anderson]

Hi,

On Wed, Apr 15, 2026 at 2:30 PM David Heidelberg via B4 Relay
<devnull+david.ixit.cz@xxxxxxxxxx> wrote:
>
> From: Guido Günther <agx@xxxxxxxxxxx>
>
> The DSI link must be powered up to let panel driver to talk to the panel
> during prepare() callback execution. Set the prepare_prev_first flag to
> guarantee this.
>
> Fixes: 9e15123eca79 ("drm/msm/dsi: Stop unconditionally powering up DSI hosts at modeset")
> Signed-off-by: Guido Günther <agx@xxxxxxxxxxx>
> Signed-off-by: David Heidelberg <david@xxxxxxx>
> ---
>  drivers/gpu/drm/panel/panel-visionox-rm69299.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/panel/panel-visionox-rm69299.c b/drivers/gpu/drm/panel/panel-visionox-rm69299.c
> index e5e688cf98fdc..0e33454650d13 100644
> --- a/drivers/gpu/drm/panel/panel-visionox-rm69299.c
> +++ b/drivers/gpu/drm/panel/panel-visionox-rm69299.c
> @@ -387,6 +387,7 @@ static int visionox_rm69299_probe(struct mipi_dsi_device *dsi)
>         dsi->format = MIPI_DSI_FMT_RGB888;
>         dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_LPM |
>                           MIPI_DSI_CLOCK_NON_CONTINUOUS;
> +       ctx->panel.prepare_prev_first = true;

Although it probably doesn't matter tons in practice, it seems like it
would be good form to set this _before_ you call drm_panel_add(). Is
there a reason you didn't do that?

-Doug