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

[Hans de Goede]

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/

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,
>>>
>