Re: Improved DRM support for cant_use_aperture platforms

[David Mosberger <davidm@napali.hpl.hp.com>]

>>>>> On 11 May 2003 23:55:33 +0200, Michel Dänzer <michel@daenzer.net> said:

  >> OK, we have a chicken & egg problem then: I could obviously add
  >> Linux kernel version checks where needed, but to do that, the
  >> patch first needs to go into the kernel.

  Michel> Mind elaborating on that? I don't see such a problem as you
  Michel> don't need version checks for anything the patch itself
  Michel> adds, only for kernel infrastructure that isn't available in
  Michel> older kernels (down to 2.4).

OK, I'm confused then: earlier on, you reported this error:

  asm/agp.h: No such file or directory

My patch adds the following to asm-i386/agp.h:

diff -Nru a/include/asm-i386/agp.h b/include/asm-i386/agp.h
--- a/include/asm-i386/agp.h	Sat May 10 01:47:42 2003
+++ b/include/asm-i386/agp.h	Sat May 10 01:47:42 2003
@@ -20,4 +20,11 @@
    worth it. Would need a page for it. */
 #define flush_agp_cache() asm volatile("wbinvd":::"memory")
 
+/*
+ * Page-protection value to be used for AGP memory mapped into kernel space.  For
+ * platforms which use coherent AGP DMA, this can be PAGE_KERNEL.  For others, it needs to
+ * be an uncached mapping (such as write-combining).
+ */
+#define PAGE_AGP			PAGE_KERNEL_NOCACHE
+
 #endif

So, either you're using a platform which I don't know supports AGP, or
the patch didn't apply cleanly (perhaps because you're using an old
kernel that doesn't have asm/agp.h yet?).

Could you shed some light?  Once I understand why things are failing
for you, I shall be happy to update the patch accordingly.

	--david