PL111 regression in v4.19-rc1

[Noralf Trønnes]

Den 27.08.2018 14.43, skrev Linus Walleij:
> On Mon, Aug 27, 2018 at 2:21 PM Noralf Trønnes <noralf at tronnes.org> wrote:
>
>> This is one suspect: 894a677f4b3e
>> drm/cma-helper: Use the generic fbdev emulation
> This doesn't revert cleanly so I couldn't try that right off.
>
> But the graphics do work before this commit.
>
> I checked out the kernel tree on this commit and it just fails
> to create the framebuffer with no messages whatsoever:
>
> versatile-tft-panel 10000000.sysreg:display at 0: no panel detected
> drm-clcd-pl111 dev:20: set up callbacks for Versatile PL110
> drm-clcd-pl111 dev:20: found bridge on endpoint 1
> drm-clcd-pl111 dev:20: Using non-panel bridge
> [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
> [drm] No driver support for vblank timestamp query.
> [drm] Initialized pl111 1.0.0 20170317 for dev:20 on minor 0
>
> I guess this somehow broke it, then some more stuff down
> the road made the damage more visible.
>
> I'm trying to see if I can fix it, any hints welcome!

I had time to look closer at this, and I don't think the fbdev change is
to blame. I think it's just that the problem shows up there because it's
the first to allocate a buffer. If the DRM side doesn't work either, I
guess the problem lies elsewhere.

Noralf.