Bug 157991

Description of problem:

The RHEL4 kernel uses the 'intel-mch-agp' driver on x86_64, not the intel-agp
driver. However, it seems that 'intel-mch-agp' is an obsolete driver. It was
removed in linux-2.6.12-rc1; see the patches titled:

<davej.org>
	[AGPGART] Drop the Intel-mch AGP driver.

<davej>
	[AGPGART] Enable Intel AGP support for x86-64 again.

(from http://www.kernel.org/pub/linux/kernel/v2.6/testing/ChangeLog-2.6.12-rc1)



The intel-mch-agp driver also lacks support for the i915 chipset found in recent
64-bit capable Intel PCs.

In order for accelerated OpenGL to work on recent x86_64 capable Intel hardware,
 the RHEL4 kernel should use the intel-agp driver on x86_64 instead of
intel-mch-agp.

Version-Release number of selected component (if applicable):

RHEL4 x86_64 kernel (2.6.9-5.0.5.EL), as well as most recent RHEL4 beta
(2.6.9-6.37.EL).

How reproducible:

Always

Steps to Reproduce:
1. try to set up accelerated OpenGL
  
Actual results:

note that the RHEL4 x86_64 kernel does not support the i915 chipset with agpgart

Expected results:

agpgart should support the same Intel chipsets on x86_64 that it does in i386

Additional info:



I built the intel-agp driver as an external module on x86_64, using the RHEL4
kernel sources (NOT a newer version of the intel-agp driver), and OpenGL worked
fine on my hardware. (pre-production Dell GX620 with i945 on-board graphics, x86_64)
(I added the PCI ID to intel-agp.c for the i945 chip, and it worked fine using
the i915 code)


I'll attach two patches to this bugzilla:

1. Dave Jones's patch to re-enable intel-agp.c for x86_64
2. A patch against kernel-2.6.9-x86_64*.config for RHEL4 to disable the
intel-mch-agp driver.

I guess you should probably also delete the intel-mch-agp driver from the RHEL4
kernel source tree as well.