Re: [Outreachy kernel] [PATCH] drm: nouveau: dispnv50: disp.c: Remove set but unused variables

["Fabio M. De Francesco" <fmdefrancesco@gmail.com>]

On Thursday, April 15, 2021 9:57:07 PM CEST Julia Lawall wrote:
> On Thu, 15 Apr 2021, Fabio M. De Francesco wrote:
> > Removed two set but unused variables.
> 
> Would it be useful to use the values?
>
It would be useful if one wants to check returns for errors (which are 
signaled by res different than 0). 

However most other drm code never checks it (as in drivers/gpu/drm/radeon/
radeon_dp_mst.c: lines 424 and 453).

Differently, drivers/gpu/drm/i915/display/intel_dp_mst.c does some logging:

ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr);
        if (ret) {
                drm_dbg_kms(&i915->drm, "failed to update payload %d\n", ret);

I could do like the second example, but I'm not sure maintainers would like 
it.

What do you think about it?

Thanks,

Fabio
> 
> julia
> 
> > Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
> > ---
> > 
> >  drivers/gpu/drm/nouveau/dispnv50/disp.c | 8 +++-----
> >  1 file changed, 3 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > b/drivers/gpu/drm/nouveau/dispnv50/disp.c index
> > 196612addfd6..828f48d5bdd4 100644
> > --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > @@ -1386,12 +1386,11 @@ nv50_mstm_cleanup(struct nv50_mstm *mstm)
> > 
> >  {
> >  
> >  	struct nouveau_drm *drm = nouveau_drm(mstm->outp->base.base.dev);
> >  	struct drm_encoder *encoder;
> > 
> > -	int ret;
> > 
> >  	NV_ATOMIC(drm, "%s: mstm cleanup\n", mstm->outp->base.base.name);
> > 
> > -	ret = drm_dp_check_act_status(&mstm->mgr);
> > +	drm_dp_check_act_status(&mstm->mgr);
> > 
> > -	ret = drm_dp_update_payload_part2(&mstm->mgr);
> > +	drm_dp_update_payload_part2(&mstm->mgr);
> > 
> >  	drm_for_each_encoder(encoder, mstm->outp->base.base.dev) {
> >  	
> >  		if (encoder->encoder_type == DRM_MODE_ENCODER_DPMST) {
> > 
> > @@ -1410,10 +1409,9 @@ nv50_mstm_prepare(struct nv50_mstm *mstm)
> > 
> >  {
> >  
> >  	struct nouveau_drm *drm = nouveau_drm(mstm->outp->base.base.dev);
> >  	struct drm_encoder *encoder;
> > 
> > -	int ret;
> > 
> >  	NV_ATOMIC(drm, "%s: mstm prepare\n", mstm->outp->base.base.name);
> > 
> > -	ret = drm_dp_update_payload_part1(&mstm->mgr);
> > +	drm_dp_update_payload_part1(&mstm->mgr);
> > 
> >  	drm_for_each_encoder(encoder, mstm->outp->base.base.dev) {
> >  	
> >  		if (encoder->encoder_type == DRM_MODE_ENCODER_DPMST) {
> > 
> > --
> > 2.31.1
> > 
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> > -1-fmdefrancesco%40gmail.com.