Hi, Arnd,
On Mon, May 30, 2022 at 11:56 PM Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
>
> On Mon, May 30, 2022 at 5:00 PM WANG Xuerui <kernel@xxxxxxxxxx> wrote:
> > On 5/30/22 21:01, Huacai Chen wrote:
> >
> > Thanks for the recognition from both of you; it is my honor and pleasure
> > to contribute to the LoongArch port and to Linux in general.
> >
> > As I'm still not entirely satisfied with my kernel development skills,
> > plus my day job is not kernel-related nor Loongson/LoongArch-related at
> > all, listing me as reviewer should be enough for now. I will take care
> > of the arch as long as I have the hardware.
>
> Thanks, sounds good to me.
>
> > BTW, there were already several breakages when rebasing the previous
> > revision (I believe it's commit 215da6d2dac0 ("MAINTAINERS: Add
> > maintainer information for LoongArch")) on top of linus' tree.
>
> Right, at least most of these should be fairly easy to address by disabling
> the corresponding features. For the allmodconfig build, I see some
> warnings that are introduced in gcc-12.1 across all architectures, and
> those can be ignored for now.
>
> Some of the errors already have fixes on top of the 215da6d2dac0
> commit, but some of the other commits look like we should leave
> them out here.
>
> I also see some conflicts between local symbol definitions and device
> drivers such as
>
> arch/loongarch/include/asm/loongarch.h:240:29: note: previous
> definition of 'csr_writel' with type 'void(u32, u32)' {aka
> 'void(unsigned int, unsigned int)'}
> 240 | static __always_inline void csr_writel(u32 val, u32 reg)
> | ^~~~~~~~~~
> drivers/media/platform/amphion/vpu_core.h:10:5: error: conflicting
> types for 'csr_readl'; have 'u32(struct vpu_core *, u32)' {aka
> 'unsigned int(struct vpu_core *, unsigned int)'}
>
> and
>
> drivers/usb/cdns3/cdns3-imx.c:85: error: "PS_MASK" redefined [-Werror]
>
> I would suggest renaming the loongarch specific symbols here, though we
> may want to also change those drivers to use less generic identifiers.
OK, loongarch specific symbols will be renamed.
>
> > Now I see
> > the loongarch-next HEAD is already rebased on top of what I believe to
> > be the current main branch, however I vaguely remember that it's not
> > good to base one's patches on top of "some random commit", so I wonder
> > whether the current branch state is appropriate for a PR?
>
> You are correct, a pull request should always be based on an -rc, orat least
> have the minimum set of dependencies. The branch was previously
> based on top of the spinlock implementation, which is still the best
> place to start here.
I have a difficult problem to select the base. Take swiotlb_init() as
an example: If I select 5.18-rc1, I should use swiotlb_init(1); if I
select Linus' latest tree, I should use swiotlb_init(true,
SWIOTLB_VERBOSE). However, if I select 5.18-rc1, linux-next will have
a build error because the code there expect swiotlb_init(true,
SWIOTLB_VERBOSE).
Huacai
>
> Arnd
