Re: [PATCH] drm/panel: boe-tv101wum-nl6: make use of prepare_prev_first

[Jessica Zhang <quic_jesszhan@quicinc.com>]

On 2/16/2024 12:31 PM, Douglas Anderson wrote:
> The panel on sc7180-trogdor-wormdingler and
> sc7180-trogdor-quackingstick hasn't been coming up since commit
> 9e15123eca79 ("drm/msm/dsi: Stop unconditionally powering up DSI hosts
> at modeset"). Let's add "prepare_prev_first" as has been done for many
> other DSI panels.
> 
> Fixes: 9e15123eca79 ("drm/msm/dsi: Stop unconditionally powering up DSI hosts at modeset")
> Signed-off-by: Douglas Anderson <dianders@chromium.org>

Hi Doug,

Reviewed-by: Jessica Zhang <quic_jesszhan@quicinc.com>

Thanks,

Jessica Zhang

> ---
> This of course gets into debates about getting a nicer solution that
> doesn't involve adding "prepare_prev_first" to every DSI panel out
> there, maybe building on Dmitry's work [1]. While it would be nice if
> we could get there, getting this landed is easy to backport to stable
> trees and gets the panel working again.
> 
> [1] https://lore.kernel.org/r/20231016165355.1327217-4-dmitry.baryshkov@linaro.org
> 
>   drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c b/drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c
> index c4c0f08e9202..bc08814954f9 100644
> --- a/drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c
> +++ b/drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c
> @@ -1871,6 +1871,8 @@ static int boe_panel_add(struct boe_panel *boe)
>   
>   	gpiod_set_value(boe->enable_gpio, 0);
>   
> +	boe->base.prepare_prev_first = true;
> +
>   	drm_panel_init(&boe->base, dev, &boe_panel_funcs,
>   		       DRM_MODE_CONNECTOR_DSI);
>   	err = of_drm_get_panel_orientation(dev->of_node, &boe->orientation);
> -- 
> 2.44.0.rc0.258.g7320e95886-goog
>