Asus M51SE video card won't work with 4GB RAM (BIOS bug ?)
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Linux |
Fix Released
|
Medium
|
|||
linux (Ubuntu) |
Fix Released
|
Undecided
|
Unassigned | ||
Bug Description
A friend of mine has a Asus M51SE laptop shipped with 4 GB of RAM. It has a video card with 256 MB of video RAM (see the attached dmesg.log).
The problem is that the prefetchable 256 MB of video memory are not assigned nowhere, even if the memory range [c0000000:cfffffff] for which the card is configured is marked as free. Strangely, usplash works perfectly while X or directfb application cannot even start.
After searching, I found that the PCI bridge (00:01.0) holding the video card (01:00.0) was configured to use a prefetchable mmio window of [bdf00000, ddefffff], which is clearly more than enough because the video card is the only device behind this bridge. It looks like a BIOS bug.
So I wrote a patch to write the correct iomem window into the bridge's BARs before resource allocation and it seems to work.
tags: | added: asus bios pci video |
summary: |
- Asus M51SE's video card won't work with 4GB RAM (BIOS bug ?) + Asus M51SE video card won't work with 4GB RAM (BIOS bug ?) |
tags: | added: hw-specific |
Changed in linux (Ubuntu): | |
status: | In Progress → Confirmed |
Changed in linux: | |
status: | Unknown → In Progress |
Changed in linux: | |
status: | In Progress → Incomplete |
Changed in linux: | |
status: | Incomplete → Fix Released |
Changed in linux: | |
importance: | Unknown → Medium |
Here comes the patch. Just append it to arch/x86/ pci/fixup. c pci-quirk" to the kernel boot arguments to activate.
Once you have compiled your kernel with the fix, add "asus-m51se-