[Intel-gfx] [PATCH i-g-t] lib/igt_debugfs: Remove support for legacy CRC api.

[Maarten Lankhorst]

Op 27-10-17 om 09:39 schreef Jani Nikula:
> On Thu, 26 Oct 2017, James Ausmus <james.ausmus at intel.com> wrote:
>> On Thu, Oct 26, 2017 at 01:38:51PM +0200, Maarten Lankhorst wrote:
>>> In kernel v4.10 the legacy crc api has been replaced by a generic
>>> drm crc API. While at it, fix igt_require_pipe_crc, the file cannot be
>>> opened any more when the crtc is not active after kernel commit 8038e09be5a3
>>> ("drm/crc: Only open CRC on atomic drivers when the CRTC is active.").
>>> Statting the file should be enough for testing it's supported.
>> What's the impact of this change on devices running older kernels - such
>> as KBL ChromeOS on 4.4?
> If you backport kernel features, you either also backport the new kernel
> CRC API, or forward port the igt support for the legacy debugfs if you
> want to use latest upstream igt?

It's part of the DRM api. Either you're using the old v4.4 kernel in which
case a lot of tests in IGT would have already failed, or when you backport
you backport the drm module too. Too much has changed between v4.4 and
drm-tip, there's no way you can just grab a current snapshot of the driver
and expect it to work in v4.4