From: Dave Airlie
Date: Sun Oct 21 2018 - 20:26:25 EST

On Mon, 22 Oct 2018 at 07:22, Michael Tirado <mtirado418@xxxxxxxxx> wrote:
> Mapping a drm "dumb" buffer fails on 32-bit system (i686) from what
> appears to be a truncated memory address that has been copied
> throughout several files. The bug manifests as an -EINVAL when calling
> mmap with the offset gathered from DRM_IOCTL_MODE_MAP_DUMB <--
> test code if needed.
> The following patch will apply to 4.18 though I've only been able to
> test through qemu bochs driver and nouveau. Intel driver worked
> without any issues. I'm not sure if everyone is going to want to
> share a constant, and the whitespace is screwed up from gmail's awful
> javascript client, so let me know if I should resend this with any
> specific changes. I have also attached the file with preserved
> whitespace.

This shouldn't be necessary, did someone misbackport the mmap changes without:

drm: set FMODE_UNSIGNED_OFFSET for drm files