Final Maverick i830, i845g, i855 support

Christopher James Halse Rogers raof at ubuntu.com
Mon Sep 13 01:20:14 UTC 2010


Hello again!

For Lucid we asked the kernel team to blacklist KMS on i830, i845 & i855
to try to work around the instability in the intel drivers on those
cards.

This instability (while, apparently, slightly reduced by the 2.12 DDX)
is still present in Maverick, so I asked the kernel team to re-enable
the blacklist in a recent upload.

Since we've got the 2.12 DDX with no userspace modesetting support, that
means that these chips should get vesa.  There's an issue¹ with X
actually loading vesa rather than fbdev or intel which I need to
investigate which is preventing this from happening now.

The other option for these cards is to use KMS + the fbdev driver².

There have been a couple of concerns raised about vesa:
 * Possibly less capable of proper suspend/resume than KMS.
 * Won't drive the display in the native mode for laptops with a
poorly-written video bios.

fbdev+KMS will work where ever KMS works, and will set the native mode
where ever KMS sets the native mode.  It is not capable of changing
resolution, however.

I've been persuaded that fbdev+KMS will provide a better experience for
more people than kms-blacklist+vesa.  This is a final call for comment
before I ask the kernel team to revert the blacklist for these cards and
flick the switch in xorg-server to use fbdev rather than intel.

¹: Bug #633593:
https://bugs.edge.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/633593
²: This is similar in some respects to the upstream “Shadow branch”
work.
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