Re: [PATCH] drm/bridge: analogix: Don't return -EINVAL when panel not support PSR in PSR functions

[Archit Taneja]

On 12/02/2016 09:33 PM, Sean Paul wrote:
> On Thu, Dec 1, 2016 at 10:54 PM, Archit Taneja <architt@xxxxxxxxxxxxxx> wrote:
> > Hi,
> >
> > On 12/02/2016 08:02 AM, zain wang wrote:
> > > We will ignored PSR setting if panel not support it. So, in this case, we
> > > should
> > > return from analogix_dp_enable/disable_psr() without any error code.
> > > Let's retrun 0 instead of -EINVAL when panel not support PSR in
> > > analogix_dp_enable/disable_psr().
> > >
> > > Signed-off-by: zain wang <wzz@xxxxxxxxxxxxxx>
> > > ---
> > >  drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 6 ++++--
> > >  1 file changed, 4 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > > b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > > index 6e0447f..0cb3695 100644
> > > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > > @@ -112,7 +112,7 @@ int analogix_dp_enable_psr(struct device *dev)
> > >         struct edp_vsc_psr psr_vsc;
> > >
> > >         if (!dp->psr_support)
> > > -               return -EINVAL;
> > > +               return 0;
> >
> >
> > Looking at the rockchip analogix dp code, in analogix_dp_psr_set, the worker
> > that calls
> > analogix_dp_enable/disable_psr isn't even if psr isn't enabled. So, the
> > bridge funcs
> > shouldn't be called in the first place. I think the error handling is fine
> > to have
> > here.
>
> Hi Archit,
>
> This was my first impression, too, and the complexity of the various
> psr abstraction layers don't help :)
>
> However, this code path will be hit if the source supports psr, but
> the sink doesn't. The rockchip_drm_psr code doesn't know if the sink
> supports psr, so it will end up calling this.

Okay, thanks for the explanation. The dev_warn() below still seems
unnecessary, right?

Archit

> Sean
>
>
> > >         /* Prepare VSC packet as per EDP 1.4 spec, Table 6.9 */
> > >         memset(&psr_vsc, 0, sizeof(psr_vsc));
> > > @@ -135,7 +135,7 @@ int analogix_dp_disable_psr(struct device *dev)
> > >         struct edp_vsc_psr psr_vsc;
> > >
> > >         if (!dp->psr_support)
> > > -               return -EINVAL;
> > > +               return 0;
> > >
> > >         /* Prepare VSC packet as per EDP 1.4 spec, Table 6.9 */
> > >         memset(&psr_vsc, 0, sizeof(psr_vsc));
> > > @@ -878,6 +878,8 @@ static void analogix_dp_commit(struct
> > > analogix_dp_device *dp)
> > >         dp->psr_support = analogix_dp_detect_sink_psr(dp);
> > >         if (dp->psr_support)
> > >                 analogix_dp_enable_sink_psr(dp);
> > > +       else
> > > +               dev_warn(dp->dev, "Sink not support PSR\n");
> >
> >
> > This doesn't seem beneficial either. There seems to be a debug
> > print already in analogix_dp_detect_sink_psr which reports PSR
> > related info.
> >
> > Archit
> >
> > >  }
> > >
> > >  /*
> >
> > --
> > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> > a Linux Foundation Collaborative Project

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project