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

[Huacai Chen]

On Tue, May 23, 2023 at 4:14 PM WANG Xuerui <kernel@xxxxxxxxxx> 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.
I suggest split the LS2K parts to a separate patch, but keep it in the
same series to get them upstreamed together.

Huacai
>
> >
> >>> +      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?
>
> --
> WANG "xen0n" Xuerui
>
> Linux/LoongArch mailing list: https://lore.kernel.org/loongarch/
>