Date: Fri, 14 Apr 2006 10:53:17 -0500 From: Jonathan Fosburgh <jonathan@fosburgh.org> To: freebsd-x11@freebsd.org Subject: i915 DRM breakage in -CURRENT Message-ID: <200604141053.25611.jonathan@fosburgh.org>
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The recent DRM commit broke the DRM on my i915 card. After digging around =
in=20
the drm sources I came across something that didn't seem right to me and=20
after changing it DRM works again. At the bottom of i915_dma.c there is a=20
comment that reads "All Intel graphics chipsets are treated as AGP...A valu=
e=20
of 1 is always retured to indictate every i9x5 is AGP." And then it is set:
int i915_driver_device_is_agp(drm_device_t * dev)
{
return 1;
}
And then in i915_drc.c, device_is_agp is set to the value of=20
i915_device_is_agp, and then drm_agpsupport.c uses this to determine if it=
=20
can attach an agp device. This used to work, but in digging through the=20
sources something caught my eye that doesn't make sense. There is a commen=
t=20
in drm_agpsupport.c that reads:
/* device_is_agp returns a tristate, 0 =3D not AGP, 1 =3D=20
definitely
* AGP, 2 =3D fall back to PCI capability
*/
But the check in the drm_device_is_agp function to determine whether or not=
to=20
attach as agp changed from
if(ret !=3D 2)
to
if(ret !=3D DRM_MIGHT_BE_AGP)
The value of DRM_MIGHT_BE_AGP is set in an enum in drmP.h
enum {
DRM_IS_NOT_AGP,
DRM_MIGHT_BE_AGP,
DRM_IS_AGP
};
I read this as DRM_IS_NOT_AGP =3D=3D 0, DRM_MIGHT_BE_AGP =3D=3D 1, and DRM_=
IS_AGP =3D=3D=20
2. Granted, in my limited coding skills I have never really used enum, but=
=20
it at least seems to me that that is what is being set. This therefore=20
conflicts with what one would expect from the comments. And based on this,=
=20
the i915 needs to be set to 2, and not 1. I have done this, and now the dr=
m=20
attaches again and appears to work (Xorg says Direct Rendering is enabled a=
nd=20
so far the appearance feels right.) The only problem I see is the drm atta=
ch=20
message says it has 0MB instead of reporting the AGP aperture size of 256MB=
,=20
as I think it used to.
agp0: <Intel 82915G (915G GMCH) SVGA controller> on vgapci0
agp0: detected 7932k stolen memory
agp0: aperture size is 256M
drm0: <Intel i915G> on vgapci0
info: [drm] AGP at 0xcfd00000 0MB
info: [drm] Initialized i915 1.4.0 20060119
HTH.
=09
=2D-=20
Jonathan Fosburgh
AIX and Storage Administrator
UT MD Anderson Cancer Center
Houston, TX
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