Re: [PATCH v2] drm/bridge: ps8640: propagate AUX transfer register errors

[Doug Anderson]

Hi,

On Thu, Jul 30, 2026 at 1:38 AM Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> wrote:
>
> On Wed, 29 Jul 2026, Doug Anderson <dianders@xxxxxxxxxxxx> wrote:
> > Hi,
> >
> > On Mon, Jul 27, 2026 at 4:40 AM Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> wrote:
> >>
> >> On Thu, 23 Jul 2026, Pengpeng Hou <pengpeng@xxxxxxxxxxx> wrote:
> >> > ps8640_aux_transfer_msg() programs the AUX address registers, starts the
> >> > AUX transfer, waits for SWAUX_SEND to clear, and reads the AUX status
> >> > register. Several of those regmap operations have return values, but the
> >> > function only checks a stale ret after the status read.
> >> >
> >> > Propagate failures from the address write, transfer start, completion
> >> > poll, and status read. This avoids returning a transfer length when the
> >> > bridge register transaction or AUX completion wait failed.
> >> >
> >> > Fixes: 13afcdd7277e ("drm/bridge: parade-ps8640: Add support for AUX channel")
> >> > Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
> >> > ---
> >> > Changes since v1: https://lore.kernel.org/all/20260623060635.16064-1-pengpeng@xxxxxxxxxxx/
> >> > - include the AUX address and length in the address-write diagnostic
> >> > - describe poll failures without assuming that every error is a timeout
> >> > - add the Fixes tag suggested by Doug
> >> > - rebase onto the current drm-misc-next tree
> >> >
> >> >  drivers/gpu/drm/bridge/parade-ps8640.c | 27 +++++++++++++++++++++------
> >> >  1 file changed, 21 insertions(+), 6 deletions(-)
> >> >
> >> > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
> >> > index 96332721cb69..56b48f8feab6 100644
> >> > --- a/drivers/gpu/drm/bridge/parade-ps8640.c
> >> > +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
> >> > @@ -257,8 +257,14 @@ static ssize_t ps8640_aux_transfer_msg(struct drm_dp_aux *aux,
> >> >       addr_len[PAGE0_SWAUX_LENGTH - base] = (len == 0) ? SWAUX_NO_PAYLOAD :
> >> >                                             ((len - 1) & SWAUX_LENGTH_MASK);
> >> >
> >> > -     regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
> >> > -                       ARRAY_SIZE(addr_len));
> >> > +     ret = regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
> >> > +                             ARRAY_SIZE(addr_len));
> >> > +     if (ret) {
> >> > +             DRM_DEV_ERROR(dev,
> >>
> >> DRM_DEV_ERROR() is deprecated in favour of drm_err() or dev_err().
> >
> > Good point. I'm inclined to land this anyway, though, since this is
> > nominally a bugfix and it matches the error printing in the rest of
> > the function. Any objections? It would be a nice future cleanup to fix
> > the error printing in this driver overall to use the non-deprecated
> > functions...
>
> Up to you.

OK, pushed to drm-misc-fixes.

[1/1] drm/bridge: ps8640: propagate AUX transfer register errors
      commit: 20697ecb299cd77b4cf8b28f655e56606b0472d8

It would be great if someone wanted to update the error prints. :-)

-Doug