Re: [git pull] drm for 4.19-rc1

From: John Stultz
Date: Thu Aug 16 2018 - 18:22:10 EST

On Thu, Aug 16, 2018 at 3:16 PM, Daniel Vetter <daniel@xxxxxxxx> wrote:
> On Thu, Aug 16, 2018 at 11:21 PM, John Stultz <john.stultz@xxxxxxxxxx> wrote:
>> On Thu, Aug 16, 2018 at 1:46 PM, Daniel Vetter <daniel@xxxxxxxx> wrote:
>>> You happen to have set drm_fb_overalloc respectively
>>> CONFIG_DRM_FBDEV_OVERALLOC? Was added so that mali blob can pageflip,
>>> would explain what's going on at least.
>> Yep. CONFIG_DRM_FBDEV_OVERALLOC is set to 200.
> So ->max_height is indeed the limit (or should be, minus driver bugs)
> for framebuffers. That's enforced in drm_framebuffer_create_internal
> for everything (both ioctl and should also for all internal callers),
> except the cma helpers never made sure this is correct. So I'd call
> this a bugfix.

Sure. I'm really not sure where the max_height=2048 comes from (and
if its the real limitation or a vendor guessed value - the hikey960
driver I have uses the same), but yea, the old code wasn't checking

> Now the question is whether the fbdev page-flipping actually worked on
> older kernels for you or not ...

It sure seems to work ok with the changes reverted. Any suggestion
on how to check this?