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

[Ville Syrjälä]

On Wed, Apr 07, 2021 at 03:50:35PM +0200, Hans de Goede wrote:
> Hi,
> 
> On 4/7/21 2:34 PM, Ville Syrjälä wrote:
> > On Tue, Apr 06, 2021 at 03:57:32PM +0200, Hans de Goede wrote:
> >> 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 at linux.intel.com>
> >>> Fixes: fe0f1e3bfdfe ("drm/i915: Shut down displays gracefully on reboot")
> >>> Signed-off-by: Hans de Goede <hdegoede at 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 ?
> > 
> > Didn't get the original mail, but lgtm.
> 
> Yeah, these bounced I mentioned that in a p.s. in one of the emails
> in our private threads about the mail issues, with patchwork links,
> but I guess the p.s. was hidden in all the other stuff in that thread.
> Anyways this is solved now.
> 
> > Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Thank you, note this is patch 1/2 does the Reviewed-by apply to
> both?  Patch 2/2 is here:
> 
> https://patchwork.freedesktop.org/patch/425983/

That one looks good as well.

Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

> 
> 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,
> >>>
> > 

-- 
Ville Syrjälä
Intel