Re: [PATCH v4 2/2] drm: bridge: ti-sn65dsi83: Disable video burst mode for LVDS stability

[Sean Nyekjaer <sean@geanix.com>]

Hi Luca,

On Wed, May 27, 2026 at 02:27:36PM +0100, Sudarshan Shetty wrote:
> The current DSI configuration enables MIPI_DSI_MODE_VIDEO_BURST.
> while burst mode is supported by the hardware, its use
> depends on continuous clock behavior from the DSI host. In practice,
> burst mode may introduce instability depending on the host controller
> implementation, as the DSI link may transition to low-power state
> between bursts.
> 
> Testing showed improved display stability when using non-burst mode on
> affected panels.
> 
> Remove MIPI_DSI_MODE_VIDEO_BURST and use non-burst video mode.
> 

We briefly talked about this at Embedded Recipes
I promised to sent a link:
https://lore.kernel.org/all/E35054BA-FBE5-4CEE-905C-1F5D20140590@geanix.com/

When burst mode is enabled, the LVDS clock gets way to high for my
panel. I don't know if it's the DSI controller in the STM32MP1 or
something not supported on the TI side.

We have been running with this fix for 2 years :)

> Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> Signed-off-by: Sudarshan Shetty <tessolveupstream@gmail.com>

Tested-by: Sean Nyekjaer <sean@geanix.com>

> ---
>  drivers/gpu/drm/bridge/ti-sn65dsi83.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
> index c03ff1ea9df8..6b5a6019c30d 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
> @@ -976,8 +976,8 @@ static int sn65dsi83_host_attach(struct sn65dsi83 *ctx)
>  
>  	dsi->lanes = dsi_lanes;
>  	dsi->format = MIPI_DSI_FMT_RGB888;
> -	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
> -			  MIPI_DSI_MODE_VIDEO_NO_HSA | MIPI_DSI_MODE_NO_EOT_PACKET;
> +	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_NO_HSA |
> +			  MIPI_DSI_MODE_NO_EOT_PACKET;
>  
>  	ret = devm_mipi_dsi_attach(dev, dsi);
>  	if (ret < 0) {
> -- 
> 2.34.1
>