Re: [PATCH v14 1/2] drm: add kms driver for loongson display controller

[Sui Jingfeng]

On 2023/5/22 16:09, WANG Xuerui wrote:
> On 2023/5/22 16:02, Sui Jingfeng wrote:
> > Hi,
> >
> > On 2023/5/21 20:21, WANG Xuerui wrote:
> > > > --- /dev/null
> > > > +++ b/drivers/gpu/drm/loongson/Kconfig
> > > > @@ -0,0 +1,17 @@
> > > > +# SPDX-License-Identifier: GPL-2.0
> > > > +
> > > > +config DRM_LOONGSON
> > > > +    tristate "DRM support for Loongson Graphics"
> > > > +    depends on DRM && PCI && MMU
> > > > +    select DRM_KMS_HELPER
> > > > +    select DRM_TTM
> > > > +    select I2C
> > > > +    select I2C_ALGOBIT
> > > > +    help
> > > > +      This is a DRM driver for Loongson Graphics, it may including
> > >
> > > Drop "it may"; "including" should be enough.
> > 'it may' is more *precise* here, because currently we don't ship with 
> > the support for loongson 2K series SoC.
> >
> > I'm try to be precise as far as I can, we avoid made this driver too 
> > large by ignore loongson 2K series SoC temporary.
>
> That's a good idea! For now the patch is so large that my review reply 
> is said to be dropped by the lists. Focusing on one bunch of similar 
> models first then adding support for the rest not-so-similar models is 
> very friendly towards the reviewing process and will help code quality 
> too.
>
> > > > +      LS7A2000, LS7A1000, LS2K2000 and LS2K1000 etc. Loongson LS7A
> > > > +      series are bridge chipset, while Loongson LS2K series are SoC.
> > > > +
> > > > +      If "M" is selected, the module will be called loongson.
> > >
> > > Just "loongson"? 
> >
> > Yes,  when compile this driver as module,  loongson.ko will be 
> > generated.
> >
> >   drm radeon is also doing so, See drm/radeon/Kconfig.
> >
> > > I know it's like this for ages (at least dating back to the MIPS 
> > > days) but you really don't want to imply Loongson is mainly a GPU 
> > > company. Something like "loongson_drm" or "lsdc" or "gsgpu" could be 
> > > better. 
> >
> > No, these name may have backward compatibility problems.
> >
> > Downstream driver already taken those name.
> >
> > userspace driver need to differentiate them who is who.
>
> IMO this shouldn't be a problem. Let me try explaining this: 
> currently, upstream / the "new world" doesn't have any support for 
> this driver at all, so any name will work; just use whatever is 
> appropriate from an upstream's perspective, then make the userspace 
> bits recognize both variants, and you'll be fine. And the "existing" 
> userspace drivers can also carry the change, it'll just be a branch 
> never taken in that setup.
>
> So, I'm still in favor of keeping the upstream "clean" without dubious 
> names like this (bare "loongson"). What do you think about my 
> suggestion above?
No,

there is a 'arm' folder in the drivers/gpu/drm/,  It doesn't say that 
arm is a pure gpu company.

there is a 'ingenic' folder in the drivers/gpu/drm/, ingenic also have 
their own custom CPUs.

there is a 'amd' folder in the drivers/gpu/drm/, these doesn't imply amd 
is mainly a GPU company.

when a folder emerged in drm/, it stand for the GPU related part of this 
company.