1. Initially - With 2GB RAM
Imac8,1 has 256MB VRAM Radeon HD2600 1920x1200
MBP4,1 has 512MB VRAM Nvidia 8600 1920x1200
Imac8,1 grub boot linux shows Video frame buffer at 90520000 and blank screen.
MBP4,1 gives 90000000 and scrambled video.
2. By overriding video_base to set it at 2GB
grub_linux_setup_video ()
video_base = 0;
grub_pci_iterate (grub_find_video_card);
/* override */
video_base = 0x80000000;
Result -
MBP gets readable text screens from kernel boot and init.
Imac gets scrambled video (better than nothing)
3. further fiddling with
grub_linux_setup_video()
params->lfb_line_len = 8192;
changed fromm 8192 to = width*4 gets clear script for Imac, but MBP wants 8192.
4. The results with 4GB RAM will differ I expect, and later effects unknown as the linux initialization is not completing (other issues with libata).
On Tue, Feb 17, 2009 at 2:02 PM, Bean
<address@hidden> wrote:
On Tue, Feb 17, 2009 at 10:56 AM, Peter Cros <
address@hidden> wrote:
> There is also a problem with Apple 64 bit grub.efi booting ubuntu 2.6.27
> linux in which the kernel is booted and starting but all video is lost after
> the boot command. I don't know if there may be a connection.
> A temporary fix is to change Video frame buufer settings in
> /loader/i386/efi/linux.c:
> grub_find_video_card and grub_linux_setup_video
> Then proceeds to the next bug (libata hangup during initrd ).
What's your frame buffer address, does grub_find_video_card detect it wrong ?
--
Bean
Cros