When innovation breaks things.

Ubuntu 10.04, Fedora 13 and other Linux distros embraced the latest graphic related innovation: KMS (kernel mode setting).

KMS, with DRM and DRI/DRI2, should bring everyone a more pleasant desktop experience, allowing the kernel to switch resolution at boot, eliminating the artifacts typical of the resolution changes managed by X. As a bonus since the framebuffer gets managed as well you also get nice 132 columns wide TTYs and some additional perks when using OpenGL.

This of course is a blatant simplification. The overall idea anyway is that there are different software layers that need to play together to have everything working properly.

Unfortunately this is what happens to me when KMS is on:

ATI Radeon X1300 + Intel 3945abg + Kernel 2.6.32.24
Fatal disconnection (bug 564376)

ATI Radeon X1300 + Intel 3945abg + Kernel 2.6.33.6
Disconnections are handled gracefully reloading the WiFi card’s firmware, but the screen goes out of sync from time to time

ATI Radeon X1300 + Intel 3945abg + Kernel 2.6.34
disconnection happens, network manager handles automatic reconnection, but again the screen goes out of sync from time to time.

Some experience more severe corruptions (with several kernel versions), others just the display going out of sync.

Examples: here here here here here.

So for now it seems that you need to choose stable WiFi / screen image (KMS off) OR 3D graphics + multi-player games (KMS on).
Again without KMS you also kiss framebuffer goodbye and this could prevent your game from running. With KMS you have framebuffer back, but WiFi (or display refresh rate) could be broken for you so your games will not last for very long.

Will these annoyances be fixed without the risk that a change in any of the above-mentioned components screws things up by accident again?
Because reading the various bug reports, and seeing what happens with different distros/kernels, I have the feeling that things get fixed “by accident” without all the people involved knowing why.

Unfortunately this situation seems quite widespread: there are no video cards unaffected, there are no video cards with good bug-free non-binary drivers, the list of WiFi card with good drivers seems pretty slim as well (according to Dan Williams).

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