[Openchrome-devel] [Bug 94473] DRM bootup error on VX900 platform

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=94473

--- Comment #11 from HuangRan <huangran at iscas.ac.cn> ---
With my initial analysis, via_driver_load() is called by DRM .load function and
via_driver_load() will do GPU initialization work including VRAM/TTM, mmmio, HW
engine,vblank and so on.
So the function via_detect_agp() is called. And an DRM function
drm_agp_acquire() then is called by via.ko which return negative value causing
this error happen.
And drm_agp_acquire() is defined in DRM file drm_agpsupport.c which we need
debug to see why negative value(-ENODEV/-EBUSY) is returned.
By contrast, The UMS driver VIADRIAgpInit() will trigger a AGP function call
drmAgpAcquire() which will call libDRM function with DRM_IOCTL_AGP_ACQUIRE,
then into DRM kernel function drm_agp_acquire_ioctl(), and finally call the
same function drm_agp_acquire() which does not cause any error!
So I believe this is something missing to do in current KMS driver I need
follow debubgging to get the root cause.

Thanks,
Frank

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/openchrome-devel/attachments/20160310/c8e453f1/attachment.html>