Re: [PATCH] drm/msm/disp: fix endian bug in debugfs code

[Dan Carpenter <dan.carpenter@oracle.com>]

On Tue, Oct 05, 2021 at 02:31:12AM +0300, Dmitry Baryshkov wrote:
> On 04/10/2021 16:47, Dan Carpenter wrote:
> > The "vbif->features" is type unsigned long but the debugfs file
> > is treating it as a u32 type.  This will work in little endian
> > systems, but the correct thing is to change the debugfs to use
> > an unsigned long.
> > 
> > Fixes: 25fdd5933e4c ("drm/msm: Add SDM845 DPU support")
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > ---
> > You might wonder why this code has so many casts.  It's required because
> > this data is const.  Which is fine because the file is read only.
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

> > 
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_vbif.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_vbif.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_vbif.c
> > index 21d20373eb8b..e645a886e3c6 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_vbif.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_vbif.c
> > @@ -305,8 +305,8 @@ void dpu_debugfs_vbif_init(struct dpu_kms *dpu_kms, struct dentry *debugfs_root)
> >   		debugfs_vbif = debugfs_create_dir(vbif_name, entry);
> > -		debugfs_create_u32("features", 0600, debugfs_vbif,
> > -			(u32 *)&vbif->features);
> > +		debugfs_create_ulong("features", 0600, debugfs_vbif,
> > +				     (unsigned long *)&vbif->features);
> 
> As you are converting this to the ulong file, could you please also remove
> the now-unnecessary type cast?

I wanted to remove all the casting but they are required because of the
const.

regards,
dan carpenter