ATI Radeon HD 5850 blank screen during boot

[lixo1]

Binary package hint: xserver-xorg-video-ati

Ubuntu 10.04 & 10.10, Kernels: 2.6.34 & 2.6.35. Using latest ATI driver from their site.
During the boot on my machine (hp envy) , before the boot screen, I got low brightness, after the login the brightness returns to normal.

If the boot uses the option quiet splash, the boot stops at the splash screen.

The problem seems to be solved when booting with acpi=off or acpi=ht.

[madbiologist (me-again)]

G'day lixo1. There seems to be a conflict in the information you have supplied. Can you please confirm whether you are using the open-source xserver-xorg-video-ati driver or the ATI Catalyst driver downloaded from the ATI website?

Note that even when using the Catalyst driver it is best to obtain it from the Ubuntu repositories in case some build fixes or compatability fixes have been added - for Natty this will be essential until ATI releases an updated driver as they have provided Ubuntu with a prerelease version of their driver.

[lixo1 (lixo1)]

Hi, thanks for your interest. This issue is independent from ati or xserver, because it happens during the boot time, before loading modules.

After a long research with kernel list I discovered that this bug comes from a conflict between video acpi and HP envy Bios model when setting brightness to the initial value. It's a kernel/hp main tree issue.

Now, there is a patch available from the main kernel source, that is shipped with kernel 2.6.38. It adds a backlight option in the boot. Here the link: https://bugzilla.kernel.org/show_bug.cgi?id=21212

So, you can close this bug report. Thanks for your interest.