Booting with gentoo option from the minimal CD installation on the HP envy 17 & 14, I observed that the screen brightness is modified to 0 when the ACPI is activated (saying [ok]).
If I use gentoo acpi=off, or gentoo acpi=ht, the problem disappears, but probably wifi, audio, etc... doesn't work anymore.
If you need further information please don't hesitate.
Steps to Reproduce:
1. Download the lastest gentoo minimal CD version.
2. Boot with gentoo option, on a HP envy 17 or 14.
3. Wait for acpi activation.
After ACPI activation brightness goes to 0 value.
Brightness should not change.
(In reply to comment #0)
This bug is also present on normal gentoo kernel >= 2.6.34.
In that case I'm reassigning this bug to the kernel team.
Have you tried: acpi_backlight=vendor as a kernel parameter?
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.
There is a patch in test, available from the main kernel source, that will be applied in the future releases > 2.6.37.
So, I close this bug report. Thanks for your interest.