Thank you, Jani. Yes, it would be good to restore the flags afterwards. I will modify the patch.
Regards
William
-----Original Message-----
From: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Sent: Tuesday, November 9, 2021 3:23 PM
To: Tseng, William <william.tseng@xxxxxxxxx>; intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Tseng, William <william.tseng@xxxxxxxxx>; Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>; Kulkarni, Vandita <vandita.kulkarni@xxxxxxxxx>; Lee, Shawn C <shawn.c.lee@xxxxxxxxx>; Chiou, Cooper <cooper.chiou@xxxxxxxxx>
Subject: Re: [PATCH] drm/i915/dsi: transmit brightness command in HS state
On Tue, 09 Nov 2021, William Tseng <william.tseng@xxxxxxxxx> wrote:
> In Video Mode, if DSI transcoder is set to transmit packets in LP
> Escape mode, screen flickering would be obseved when brightness
> commands are continuously and quickly transmitted to a panel.
>
> The problem may be resolved by changing the mode to transmit packets
> from Low Power to HS.
>
> Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
> Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> Cc: Vandita Kulkarni <vandita.kulkarni@xxxxxxxxx>
> Cc: Lee Shawn C <shawn.c.lee@xxxxxxxxx>
> Cc: Cooper Chiou <cooper.chiou@xxxxxxxxx>
> Signed-off-by: William Tseng <william.tseng@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c
> b/drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c
> index f61ed82e8867..a71ef1eb598c 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsi_dcs_backlight.c
> @@ -81,6 +81,7 @@ static void dcs_set_backlight(const struct
> drm_connector_state *conn_state, u32
>
> for_each_dsi_port(port, intel_dsi->dcs_backlight_ports) {
> dsi_device = intel_dsi->dsi_hosts[port]->device;
> + dsi_device->mode_flags &= ~MIPI_DSI_MODE_LPM;
Frankly I forget how this is intended to be used, but feels like you should maybe restore the flags afterwards.
BR,
Jani.
> mipi_dsi_dcs_write(dsi_device, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
> &data, len);
> }
--
Jani Nikula, Intel Open Source Graphics Center
