Messages in this thread | | | Date | Sat, 27 Jul 2013 13:19:16 -0400 | From | Cristian Rodríguez <> | Subject | acpi_backlight=vendor no longer working around buggy laptop from hell |
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Hi:
I have a DELL XPS 15z laptop with the latest BIOS (A12).
This piece of crap have never worked properly without special boot parameters. Up to kernel 3.10, passing acpi_backlight=vendor was enough to allow the machine to complete boot and be usable.
Now with 3.11 rc2 (also with today's linus tree) unbootable machine problem is back.
In the past I spent many hours figuring out workarounds and they go _now_ as the following.
Booting with:
"nox2apic" --> machine works, flawless.
"x2apic_phys acpi_backlight=vendor" --> machine works, except for the big problem that the laptop keyboard and touchpad are unresponsive, I have to plug USB keyboard/mouse to get anything done.
With no boot parameters the machine hangs at random points in the boot sequence either:
-Very early at boot and there is no way to retrieve any useful debug info. [OR]
- Somehow it looses "connection" with the ATA controller and the filesystems cannot be mounted. [OR]
- In very few ocassions, the boot proceeds with no keyboard or touchpad then the iwlwifi wireless card does something stupid (firmware error...)
The only possible hint in the logs I could ever find is:
[ 3.844586] [Firmware Bug]: ACPI(PEGP) defines _DOD but not _DOS
I tried in the past to obtain any debug information, with no luck.
Help is appreciated to get to the bottom of the problem. ;)
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