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User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.3) Gecko/20030314

Description of problem:
On a kernel built with HIGHMEM support (4GB in my case), booting with the kernel
option "vga=0x305" or any similar graphics mode causes the kernel to immediately
hang with a blank screen at the beginning of the boot sequence.

Version-Release number of selected component (if applicable):
kernel-2.4.18-* and/or kernel-2.4.20-*

How reproducible:
Always

Steps to Reproduce:
1. Build custom kernel with HIGHMEM support.
2. Add kernel boot option "vga=0x305".
3. Try to boot new kernel.
    

Actual Results:  See Description.

Expected Results:  Kernel should have booted.

Additional Information:
Although my system is an Athlon platform, I doubt that has anything to do with
it. It's probably a generic i386 problem?  Also, maybe this only happens if the
system actually tries to use the high memory? I didn't try to boot the kernel on
a system with less than 1 GB of RAM.

Kernel 2.4.21-rc2 has a fix for this which is easily back-ported. In
"drivers/video/vesafb.c", replace the line

    video_size = screen_info.lfb_size * 65536;

with the following line:

    video_size = screen_info.lfb_width * screen_info.lfb_height * video_bpp;