G5 Quad hangs early on 4.20.2 / 5.0-rc2+

[Mathieu Malaterre]

On Fri, Jan 18, 2019 at 1:53 AM Tobias Ulmer <tobiasu at tmux.org> wrote:
>
> On Fri, Jan 18, 2019 at 09:32:07AM +1100, Benjamin Herrenschmidt wrote:
> > On Thu, 2019-01-17 at 10:42 +0100, Tobias Ulmer wrote:
> > > On Wed, Jan 16, 2019 at 12:15:14PM +1100, Benjamin Herrenschmidt wrote:
> > > > On Tue, 2019-01-15 at 23:49 +0100, Tobias Ulmer wrote:
> > > > > Hi,
> > > > >
> > > > > both the latest stable 4.20.2 and 5.0 rc2+ hang early on the G5 Quad.
> > > > >
> > > > > Surely I'm not the first to run into this, but I couldn't find any
> > > > > discussion or bug report. Sorry if you're already aware.
> > > > >
> > > > > You can see it hang here (5.0 rc2+, 4.20.2 is nearly identical) until
> > > > > the watchdog triggers a reboot:
> > > > >
> > > > > https://i.imgur.com/UiCVRuG.jpg
> > > > >
> ...
> > I'll be back on monday or tuesday, let me know where you got up to then
> > and I'll take it from there. Also email me your .config please.
>
>
> Hi,
>
> this was caused by 5c63e407aaabb0464236cfc6279a2d79aede7073
> (fbdev: Convert to using %pOFn instead of device_node.name)

See:

https://patchwork.kernel.org/patch/10750931/



> name can't be NULL into offb_init_fb, there's a printk and the call to
> offb_init_palette_hacks where name is matched against OF device names.
>
> With the partial revert below, both 5.0-rc2+ and 4.20 are happy.
>
> diff --git a/drivers/video/fbdev/offb.c b/drivers/video/fbdev/offb.c
> index 31f769d67195..77c0a2f45b3b 100644
> --- a/drivers/video/fbdev/offb.c
> +++ b/drivers/video/fbdev/offb.c
> @@ -419,13 +419,9 @@ static void __init offb_init_fb(const char *name,
>         var = &info->var;
>         info->par = par;
>
> -       if (name) {
> -               strcpy(fix->id, "OFfb ");
> -               strncat(fix->id, name, sizeof(fix->id) - sizeof("OFfb "));
> -               fix->id[sizeof(fix->id) - 1] = '\0';
> -       } else
> -               snprintf(fix->id, sizeof(fix->id), "OFfb %pOFn", dp);
> -
> +       strcpy(fix->id, "OFfb ");
> +       strncat(fix->id, name, sizeof(fix->id) - sizeof("OFfb "));
> +       fix->id[sizeof(fix->id) - 1] = '\0';
>
>         var->xres = var->xres_virtual = width;
>         var->yres = var->yres_virtual = height;
> @@ -648,7 +644,7 @@ static void __init offb_init_nodriver(struct device_node *dp, int no_real_node)
>                 /* kludge for valkyrie */
>                 if (strcmp(dp->name, "valkyrie") == 0)
>                         address += 0x1000;
> -               offb_init_fb(no_real_node ? "bootx" : NULL,
> +               offb_init_fb(no_real_node ? "bootx" : dp->name,
>                              width, height, depth, pitch, address,
>                              foreign_endian, no_real_node ? NULL : dp);
>         }