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Re: [RFC][PATCH 1/3] drm/bridge: adv7511: Rework adv7511_power_on/off() so they can be reused internally

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Hi John,

On Tuesday 22 Nov 2016 09:25:22 John Stultz wrote:
> On Tue, Nov 22, 2016 at 12:14 AM, Laurent Pinchart wrote:
> > On Monday 21 Nov 2016 16:37:30 John Stultz wrote:
>  @@ -545,24 +554,13 @@ static int adv7511_get_modes(struct adv7511 *adv7511,
> >>       unsigned int count;
> >>       
> >>       /* Reading the EDID only works if the device is powered */
> >> 
> >> -     if (!adv7511->powered) {
> >> -             regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER,
> >> -                                ADV7511_POWER_POWER_DOWN, 0);
> >> -             if (adv7511->i2c_main->irq) {
> >> -                     regmap_write(adv7511->regmap,
> >> ADV7511_REG_INT_ENABLE(0),
> >> -                                  ADV7511_INT0_EDID_READY);
> >> -                     regmap_write(adv7511->regmap,
> >> ADV7511_REG_INT_ENABLE(1),
> >> -                                  ADV7511_INT1_DDC_ERROR);
> >> -             }
> >> -             adv7511->current_edid_segment = -1;
> >> -     }
> >> +     if (!adv7511->powered)
> >> +             __adv7511_power_on(adv7511);
> > 
> > The __adv7511_power_on() function does more than the above, in particular
> > it performs an expensive regcache_sync() and calls adv7533_dsi_power_on()
> > for the ADV7533. Don't those operations have side effects that are either
> > not wanted or not needed here ? In any case this patch modifies the
> > behaviour of the driver, which needs to be documented in the kernel
> > message.
> 
> So yes, while the adv7533 bits aren't needed in the internal function,
> I'm finding the logic to pulse the HPD and the regcache_sync call seem
> to be needed side effects, as without that logic, I get i2c_transfer()
> errors in adv7511_get_edid_block().

Does this patch fix the problem without requiring the 200ms delay ?

> I'll try to rework this patch to split the two changes of reworking
> the power_on/off function to be re-used (with no logic chage), and the
> patch to reuse it in get_modes() which resolves a bug.

Have you identified which register write fixes your problem here ?

> Thanks so much for the review!

-- 
Regards,

Laurent Pinchart

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[RFC][PATCH 0/3] adv7511 EDID probing improvements John Stultz <john.stultz@linaro.org> - 2016-11-22 01:40 +0100
  [RFC][PATCH 3/3] drm/bridge: adv7511: Enable HPD interrupts to support hotplug and improve monitor detection John Stultz <john.stultz@linaro.org> - 2016-11-22 01:40 +0100
    Re: [RFC][PATCH 3/3] drm/bridge: adv7511: Enable HPD interrupts to support hotplug and improve monitor detection Laurent Pinchart <laurent.pinchart@ideasonboard.com> - 2016-11-22 09:30 +0100
  [RFC][PATCH 1/3] drm/bridge: adv7511: Rework adv7511_power_on/off() so they can be reused internally John Stultz <john.stultz@linaro.org> - 2016-11-22 01:40 +0100
    Re: [RFC][PATCH 1/3] drm/bridge: adv7511: Rework adv7511_power_on/off() so they can be reused internally Laurent Pinchart <laurent.pinchart@ideasonboard.com> - 2016-11-22 09:20 +0100
      Re: [RFC][PATCH 1/3] drm/bridge: adv7511: Rework adv7511_power_on/off()  so they can be reused internally John Stultz <john.stultz@linaro.org> - 2016-11-22 09:20 +0100
        Re: [RFC][PATCH 1/3] drm/bridge: adv7511: Rework adv7511_power_on/off() so they can be reused internally Laurent Pinchart <laurent.pinchart@ideasonboard.com> - 2016-11-22 09:30 +0100
      Re: [RFC][PATCH 1/3] drm/bridge: adv7511: Rework adv7511_power_on/off()  so they can be reused internally John Stultz <john.stultz@linaro.org> - 2016-11-22 18:30 +0100
        Re: [RFC][PATCH 1/3] drm/bridge: adv7511: Rework adv7511_power_on/off() so they can be reused internally Laurent Pinchart <laurent.pinchart@ideasonboard.com> - 2016-11-22 18:40 +0100
          Re: [RFC][PATCH 1/3] drm/bridge: adv7511: Rework adv7511_power_on/off()  so they can be reused internally John Stultz <john.stultz@linaro.org> - 2016-11-22 18:50 +0100
          Re: [RFC][PATCH 1/3] drm/bridge: adv7511: Rework adv7511_power_on/off()  so they can be reused internally John Stultz <john.stultz@linaro.org> - 2016-11-22 20:50 +0100
            Re: [RFC][PATCH 1/3] drm/bridge: adv7511: Rework  adv7511_power_on/off() so they can be reused internally Archit Taneja <architt@codeaurora.org> - 2016-11-23 05:00 +0100
  [RFC][PATCH 2/3] drm/bridge: adv7511: Add 200ms delay on power-on John Stultz <john.stultz@linaro.org> - 2016-11-22 01:40 +0100
    Re: [RFC][PATCH 2/3] drm/bridge: adv7511: Add 200ms delay on power-on Laurent Pinchart <laurent.pinchart@ideasonboard.com> - 2016-11-22 09:30 +0100
      Re: [RFC][PATCH 2/3] drm/bridge: adv7511: Add 200ms delay on power-on John Stultz <john.stultz@linaro.org> - 2016-11-22 18:50 +0100
        Re: [RFC][PATCH 2/3] drm/bridge: adv7511: Add 200ms delay on power-on John Stultz <john.stultz@linaro.org> - 2016-11-22 19:20 +0100
          Re: [RFC][PATCH 2/3] drm/bridge: adv7511: Add 200ms delay on power-on Laurent Pinchart <laurent.pinchart@ideasonboard.com> - 2016-11-22 19:30 +0100
            Re: [RFC][PATCH 2/3] drm/bridge: adv7511: Add 200ms delay on power-on John Stultz <john.stultz@linaro.org> - 2016-11-22 20:00 +0100
            Re: [RFC][PATCH 2/3] drm/bridge: adv7511: Add 200ms delay on power-on Daniel Vetter <daniel@ffwll.ch> - 2016-11-23 09:00 +0100
              Re: [RFC][PATCH 2/3] drm/bridge: adv7511: Add 200ms delay on power-on Laurent Pinchart <laurent.pinchart@ideasonboard.com> - 2016-11-25 01:30 +0100
                Re: [RFC][PATCH 2/3] drm/bridge: adv7511: Add 200ms delay on power-on Daniel Vetter <daniel@ffwll.ch> - 2016-11-25 07:40 +0100

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