[bug report] drm/msm: dsi: Handle dual-channel for 6G as well

[Dmitry Baryshkov]

On Fri, 15 Oct 2021 at 04:43, Jessica Zhang <jesszhan at codeaurora.org> wrote:
>
> Hey Dan,
>
> On 10/1/2021 5:31 AM, Dan Carpenter wrote:
> > Hello Sean Paul,
> >
> > The patch a6bcddbc2ee1: "drm/msm: dsi: Handle dual-channel for 6G as
> > well" from Jul 25, 2018, leads to the following
> > Smatch static checker warning:
> >
> >       drivers/gpu/drm/msm/dsi/dsi_host.c:729 dsi_calc_clk_rate_6g()
> >       warn: wrong type for 'msm_host->esc_clk_rate' (should be 'ulong')
> >
> > drivers/gpu/drm/msm/dsi/dsi_host.c
> >      721 int dsi_calc_clk_rate_6g(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
> >      722 {
> >      723         if (!msm_host->mode) {
> >      724                 pr_err("%s: mode not set\n", __func__);
> >      725                 return -EINVAL;
> >      726         }
> >      727
> >      728         dsi_calc_pclk(msm_host, is_bonded_dsi);
> > --> 729         msm_host->esc_clk_rate = clk_get_rate(msm_host->esc_clk);
> >                  ^^^^^^^^^^^^^^^^^^^^^^
> > I don't know why Smatch is suddenly warning about ancient msm code, but
> > clock rates should be unsigned long.  (I don't remember why).
> >
> >      730         return 0;
> >      731 }
>
> I'm unable to recreate the warning with Smatch. After running
> build_kernel_data.sh, I ran `<path to smatch>/smatch_scripts/kchecker
> drivers/gpu/drm/msm/dsi/dsi_host.c` and got the following output:
>
> CHECK scripts/mod/empty.c
> CALL scripts/checksyscalls.sh
> CALL scripts/atomic/check-atomics.sh
> CHECK arch/arm64/kernel/vdso/vgettimeofday.c
> CC drivers/gpu/drm/msm/dsi/dsi_host.o
> CHECK drivers/gpu/drm/msm/dsi/dsi_host.c
> drivers/gpu/drm/msm/dsi/dsi_host.c:2380 msm_dsi_host_power_on() warn:
> missing error code 'ret'
>
> Is there a specific .config you're using (that's not the default
> mainline defconfig)? If so, can you please share it?

Are you running your checks with ARM32 or ARM64 in mind?
Note, esc_clk_rate is u32, while clk_get_rate()'s returns unsigned long.
It would make sense to change all three clocks rates in msm_dsi_host
struct (and several places where they are used) to unsigned long.

>
> Thanks,
>
> Jessica Zhang
>
> > regards,
> > dan carpenter



-- 
With best wishes
Dmitry