Re: [PATCH 1/2] drm/i915/display/vlv_dsi: Do not skip panel_pwr_cycle_delay when disabling the panel

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 3/25/21 12:48 PM, Hans de Goede wrote:
> After the recently added commit fe0f1e3bfdfe ("drm/i915: Shut down
> displays gracefully on reboot"), the DSI panel on a Cherry Trail based
> Predia Basic tablet would no longer properly light up after reboot.
> 
> I've managed to reproduce this without rebooting by doing:
> chvt 3; echo 1 > /sys/class/graphics/fb0/blank;\
> echo 0 > /sys/class/graphics/fb0/blank
> 
> Which rapidly turns the panel off and back on again.
> 
> The vlv_dsi.c code uses an intel_dsi_msleep() helper for the various delays
> used for panel on/off, since starting with MIPI-sequences version >= 3 the
> delays are already included inside the MIPI-sequences.
> 
> The problems exposed by the "Shut down displays gracefully on reboot"
> change, show that using this helper for the panel_pwr_cycle_delay is
> not the right thing to do. This has not been noticed until now because
> normally the panel never is cycled off and directly on again in quick
> succession.
> 
> Change the msleep for the panel_pwr_cycle_delay to a normal msleep()
> call to avoid the panel staying black after a quick off + on cycle.
> 
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Fixes: fe0f1e3bfdfe ("drm/i915: Shut down displays gracefully on reboot")
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Ping? Ville AFAICT this is ready for merging, can you review this please so that I can push it to drm-intel-next ?

Regards,

Hans


> ---
>  drivers/gpu/drm/i915/display/vlv_dsi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/vlv_dsi.c b/drivers/gpu/drm/i915/display/vlv_dsi.c
> index d5a3f69c5df3..38d5a1f3ded5 100644
> --- a/drivers/gpu/drm/i915/display/vlv_dsi.c
> +++ b/drivers/gpu/drm/i915/display/vlv_dsi.c
> @@ -996,14 +996,14 @@ static void intel_dsi_post_disable(struct intel_atomic_state *state,
>  	 * FIXME As we do with eDP, just make a note of the time here
>  	 * and perform the wait before the next panel power on.
>  	 */
> -	intel_dsi_msleep(intel_dsi, intel_dsi->panel_pwr_cycle_delay);
> +	msleep(intel_dsi->panel_pwr_cycle_delay);
>  }
>  
>  static void intel_dsi_shutdown(struct intel_encoder *encoder)
>  {
>  	struct intel_dsi *intel_dsi = enc_to_intel_dsi(encoder);
>  
> -	intel_dsi_msleep(intel_dsi, intel_dsi->panel_pwr_cycle_delay);
> +	msleep(intel_dsi->panel_pwr_cycle_delay);
>  }
>  
>  static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
> 

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