Re: [PATCH v10 2/2] drm: add kms driver for loongson display controller

[Sui Jingfeng]

Hi,

On 2023/4/4 22:10, Emil Velikov wrote:
> > --- /dev/null
> > +++ b/drivers/gpu/drm/loongson/lsdc_debugfs.c
> > +void lsdc_debugfs_init(struct drm_minor *minor)
> > +{
> > +#ifdef CONFIG_DEBUG_FS
> > +       drm_debugfs_create_files(lsdc_debugfs_list,
> > +                                ARRAY_SIZE(lsdc_debugfs_list),
> > +                                minor->debugfs_root,
> > +                                minor);
> > +#endif
> > +}
> Should probably build the file when debugfs is enabled and provide
> no-op stub in the header. See nouveau for an example.
But doing that way introduce duplication,  you actually write two 
implements for the same function prototype.

One for the real, another one for the dummy.

Typically skilled core framework programmer/writer like it, for multiple 
backend and multiple arch support

Because the functions set need to be implemented is large for those cases.

While we are just a driver implement based the drm core and only one 
single function here,

DEBUG_FS is enabled by default on our Mips and Loongarch. It is not 
suffer from high frequency changes.

In this case , CONFIG_DEBUG_FS just boils down to "true", a nearly 
always enabled decoration.


We do implement debugfs support that way in the before[1], but we pursue 
compact in the afterwards.

We could revise our driver if that is strongly recommended.


[1] https://patchwork.freedesktop.org/patch/480521/