Re: [PATCH v3 05/43] drm/bridge: analogix_dp: Don't power bridge in analogix_dp_bind

[Marek Szyprowski]

Hi Heiko,

Thanks for adding me to this thread.

On 2018-02-28 16:20, Heiko StÃbner wrote:
> Am Dienstag, 30. Januar 2018, 21:28:35 CET schrieb Thierry Escande:
> > From: zain wang <wzz@xxxxxxxxxxxxxx>
> >
> > The bridge does not need to be powered in analogix_dp_bind(), so
> > remove the calls to pm_runtime_get()/phy_power_on()/analogix_dp_init_dp()
> > as well as their power-off counterparts.
> >
> > Cc: StÃphane Marchesin <marcheu@xxxxxxxxxxxx>
> > Signed-off-by: zain wang <wzz@xxxxxxxxxxxxxx>
> > Signed-off-by: Caesar Wang <wxt@xxxxxxxxxxxxxx>
> > [the patch originally just removed the power_on portion, seanpaul removed
> > the power off code as well as improved the commit message]
> > Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
> > Signed-off-by: Thierry Escande <thierry.escande@xxxxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 10 ----------
> >   1 file changed, 10 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index
> > cb5e18d6ba04..1477ea9ba85d 100644
> > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > @@ -1382,11 +1382,6 @@ analogix_dp_bind(struct device *dev, struct
> > drm_device *drm_dev,
> >
> >   	pm_runtime_enable(dev);
> >
> > -	pm_runtime_get_sync(dev);
> > -	phy_power_on(dp->phy);
> > -
> > -	analogix_dp_init_dp(dp);
> > -
> >   	ret = devm_request_threaded_irq(&pdev->dev, dp->irq,
> >   					analogix_dp_hardirq,
> >   					analogix_dp_irq_thread,
> > @@ -1414,15 +1409,10 @@ analogix_dp_bind(struct device *dev, struct
> > drm_device *drm_dev, goto err_disable_pm_runtime;
> >   	}
> >
> > -	phy_power_off(dp->phy);
> > -	pm_runtime_put(dev);
> > -
> >   	return dp;
> >
> >   err_disable_pm_runtime:
> >
> > -	phy_power_off(dp->phy);
> > -	pm_runtime_put(dev);
> >   	pm_runtime_disable(dev);
> >
> >   	return ERR_PTR(ret);
> In general, this patch seems to also create the opposite than
> "drm/bridge: analogix_dp: Keep PHY powered between driver bind/unbind" [0]
>
> posted on monday?
>
> [0] https://patchwork.kernel.org/patch/10242493/

Well, my patch was a quick workaround to avoid board freeze.

This patch looks like a proper fix. Besides removing runtime pm and phy
power calls from dp_bind, it also removes dp register access done in
analogix_dp_init_dp, as there is really no need to touch registers in bind
operation.

The patchset however suffers from other issues on Exynos hardware. I 
will post
them in that thread.

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland