Re: [Libreboot] X60 tablet: screen whine after 1400x1050 screen swap

[Charles Devereaux]

I much prefer not having to flash non free software (and even after extracting and adding the vgarom based on http://www.coreboot.org/VGA_support and https://github.com/bibanon/Coreboot-ThinkPads/wiki/T60p-Extract-VGABIOS-From-Backup, I still can't read the value with devmem2 anyway - it always returns 0)

I flashed back free software and intel_reg gives the following:

gpu_hotplug = 0x00000220
gpu_lvds_use_spread_spectrum_clock = 1
gpu_lvds_is_dual_channel = 0
gpu_backlight = 0x879f87da
backlight modulation frequency = 180.016706 Hz
duty cycle = 100%
legacy backlight brightness = 0x83

About the intel_bios_reader, I passed the oprom_0.rom and got the attached output. Apparently it still thinks I have a type 2 (1024x768) panel instead of the1400x1050 (type 4 or 5) I installed.

None of the frequencies match. (180 vs 122 vs 162)

Previously, 0x879f879e gave the uneven backlight problem.
Using 0x79417940 everything works fine, but with a lesser whine -- yet intel_regs.py gives me that 0x879f87da or 0x879f87e6 when I tweak the brightness

At this point I'm not sure what I should do. Any other suggestion is welcome.

On Thu, Apr 16, 2015 at 12:45 PM, Michał Masłowski <address@hidden> wrote:

> http://libreboot.org/gitdocs/future/old.html#x60_native_notes
> Just follow the same method, but on your X60 Tablet, and you read from
> 0xe4361254 location in devmem to get the proper value.

Don't recommend accessing fixed memory locations.
http://hg.mtjm.eu/scripts/file/tip/intel-regs.py reads it in a way
independent of where your system maps PCI regions.  (That script is
inefficient and has wrong comments.  I do not know proper tools for
doing exactly this in scripts.)

The intel_bios_reader program (in intel-gpu-tools) also prints the PWM
frequency from which the register value can be computed.

oprom.txt
Description: Text document