Re: [PATCH 2.4.29-pre1] radeonfb: don't try to ioreamp the entire VRAM [was: Re: [Linux-fbdev-devel] why does radeonfb work fine in 2.6, but not in 2.4.29-pre1?]

Il Sun, Nov 28, 2004 at 07:46:06PM +0100, Jurriaan ha scritto: 

quoted

The same radeonfb-setup works fine in every 2.6 kernel I can remember
(last tested with 2.6.10-rc2-mm3) but give the dreaded 'cannot map FB'
in 2.4.29-pre1.

The card has 128 MB of ram, and my system has 3 GB of RAM.

Is there any reason the ioremap() call works on 2.6, but doesn't on 2.4?

I've tried searching google for hints, but nothing has turned up.

Is there any way to test 2.4 with my radeonfb and all of my memory?

I sent you a patch a while ago but was discarded because introduced a
subtle API change. This time should be ok :)

Make fb layer aware of the difference between the ioremap()'ed VRAM and
total available VRAM.
smem_len in struct fb_fix_screeninfo still contains the amount of
physical VRAM (reported to userspace via FBIOGET_FSCREENINFO ioctl) and
the new field mapped_vram contains the amount of VRAM actually
ioremap()'ed by drivers (used in read/write/mmap operations).
Since there was unused padding at the end of struct fb_fix_screeninfo
binary compatibility with userspace utilities is retained.
If mapped_vram is not set it's assumed that the entire framebuffer is
mapped, thus other drivers are unaffected by this patch.

The patch has been tested by Jurriaan [off-list ref].

Signed-off-by: Luca Tettamanti <redacted>

--- a/include/linux/fb.h	2004-11-30 18:30:08.000000000 +0100
+++ b/include/linux/fb.h	2004-11-30 18:33:00.000000000 +0100

@@ -126,7 +126,8 @@
 					/* (physical address) */
 	__u32 mmio_len;			/* Length of Memory Mapped I/O  */
 	__u32 accel;			/* Type of acceleration available */
-	__u16 reserved[3];		/* Reserved for future compatibility */
+	__u32 mapped_vram;		/* Amount of ioremap()'ed VRAM */
+	__u16 reserved[1];		/* Reserved for future compatibility */
 };