2021-04-30 22:35:33

by Lyude Paul

Subject: [PATCH 2/2] drm/dp: Drop open-coded drm_dp_is_branch() in drm_dp_read_downstream_info()

Noticed this while fixing another issue in drm_dp_read_downstream_info(),
the open coded DP_DOWNSTREAMPORT_PRESENT check here just duplicates what we
already do in drm_dp_is_branch(), so just get rid of it.

Signed-off-by: Lyude Paul <[email protected]>
---
drivers/gpu/drm/drm_dp_helper.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 27c8c5bdf7d9..0f84df8798ab 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -677,9 +677,7 @@ int drm_dp_read_downstream_info(struct drm_dp_aux *aux,
memset(downstream_ports, 0, DP_MAX_DOWNSTREAM_PORTS);

/* No downstream info to read */
- if (!drm_dp_is_branch(dpcd) ||
- dpcd[DP_DPCD_REV] < DP_DPCD_REV_10 ||
- !(dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT))
+ if (!drm_dp_is_branch(dpcd) || dpcd[DP_DPCD_REV] < DP_DPCD_REV_10)
return 0;

/* Some branches advertise having 0 downstream ports, despite also advertising they have a
--
2.30.2

2021-05-03 03:08:39

by Ville Syrjälä

Subject: Re: [Intel-gfx] [PATCH 2/2] drm/dp: Drop open-coded drm_dp_is_branch() in drm_dp_read_downstream_info()

On Fri, Apr 30, 2021 at 06:34:28PM -0400, Lyude Paul wrote:
> Noticed this while fixing another issue in drm_dp_read_downstream_info(),
> the open coded DP_DOWNSTREAMPORT_PRESENT check here just duplicates what we
> already do in drm_dp_is_branch(), so just get rid of it.
>
> Signed-off-by: Lyude Paul <[email protected]>
> ---
> drivers/gpu/drm/drm_dp_helper.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> index 27c8c5bdf7d9..0f84df8798ab 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -677,9 +677,7 @@ int drm_dp_read_downstream_info(struct drm_dp_aux *aux,
> memset(downstream_ports, 0, DP_MAX_DOWNSTREAM_PORTS);
>
> /* No downstream info to read */
> - if (!drm_dp_is_branch(dpcd) ||
> - dpcd[DP_DPCD_REV] < DP_DPCD_REV_10 ||
> - !(dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT))
> + if (!drm_dp_is_branch(dpcd) || dpcd[DP_DPCD_REV] < DP_DPCD_REV_10)

BTW that DPCD_REV check looks rather wrong.

Reviewed-by: Ville Syrj?l? <[email protected]>

> return 0;
>
> /* Some branches advertise having 0 downstream ports, despite also advertising they have a
> --
> 2.30.2
>
> _______________________________________________
> Intel-gfx mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
Ville Syrj?l?
Intel

2021-05-07 21:30:07

by Lyude Paul

Subject: Re: [Intel-gfx] [PATCH 2/2] drm/dp: Drop open-coded drm_dp_is_branch() in drm_dp_read_downstream_info()

On Mon, 2021-05-03 at 06:06 +0300, Ville Syrjälä wrote:
> On Fri, Apr 30, 2021 at 06:34:28PM -0400, Lyude Paul wrote:
> > Noticed this while fixing another issue in drm_dp_read_downstream_info(),
> > the open coded DP_DOWNSTREAMPORT_PRESENT check here just duplicates what
> > we
> > already do in drm_dp_is_branch(), so just get rid of it.
> >
> > Signed-off-by: Lyude Paul <[email protected]>
> > ---
> >  drivers/gpu/drm/drm_dp_helper.c | 4 +---
> >  1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_dp_helper.c
> > b/drivers/gpu/drm/drm_dp_helper.c
> > index 27c8c5bdf7d9..0f84df8798ab 100644
> > --- a/drivers/gpu/drm/drm_dp_helper.c
> > +++ b/drivers/gpu/drm/drm_dp_helper.c
> > @@ -677,9 +677,7 @@ int drm_dp_read_downstream_info(struct drm_dp_aux
> > *aux,
> >         memset(downstream_ports, 0, DP_MAX_DOWNSTREAM_PORTS);
> >  
> >         /* No downstream info to read */
> > -       if (!drm_dp_is_branch(dpcd) ||
> > -           dpcd[DP_DPCD_REV] < DP_DPCD_REV_10 ||
> > -           !(dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT))
> > +       if (!drm_dp_is_branch(dpcd) || dpcd[DP_DPCD_REV] < DP_DPCD_REV_10)
>
> BTW that DPCD_REV check looks rather wrong.
>
> Reviewed-by: Ville Syrjälä <[email protected]>

I'll send out a separate fix for this in just a moment, thanks for pointing it
out!

>
> >                 return 0;
> >  
> >         /* Some branches advertise having 0 downstream ports, despite also
> > advertising they have a
> > --
> > 2.30.2
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > [email protected]
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
>

--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat