On Wed, Apr 3, 2013 at 5:21 PM, Kero kero@chello.nl wrote:
Hi,
I would not mind improving use of my Asus EeePC X101CH with Cedar View / gma3600 a bit more. But a barrier is knowledge of the hardware. Meddling with existing (initialization) code is possible, but for point 1 and 3 below that is not going to cut, it, I expect.
It would be very useful if you could help out with cedarview. Even if it's just by testing patches. A big problem for me is that I don't have the hardware so it's easy to break things without even knowing about it.
Does anyone have pointers? Who should I talk to about specifications? I know Intel is not forthcoming with documentation, yet several people have made contributions for poulsbo and later versions of the hardware. How did you get the required knowledge?
Most of the mode setting stuff are variations of Intel hardware. You can find specifications at https://01.org/linuxgraphics/ and it's also useful to look at the Intel i915 drm driver for reference. It is quite a mix so you need to look at bits and pieces from several of the Intel generations and try to match them together.
For the non-Intel parts there are some drivers that never made it into mainline but is still available online. Some parts are open and some are closed.
There is also a fair amount of guessing and probing needed.
Things I might, in order of personal preference, in due time (after holiday), take a look at:
- would be nice to have the full 1024x600 on the external VGA and HDMI I had a chance to try another monitor over HDMI, same result: only 800x600 visible.
- booting with either VGA or HDMI plugged in, yields two black screens: both the laptop and the monitor. Un- + re-plugging has no visible effect.
- the Fn keys for the backlight induce a response in the backlight, but only with tiny results; /sys/class/backlight/psb-bl/brightness works fine, though
- when using modules, initialization from hibernation is not good enough: my screen stays black; without using modules, the kernel boots normally, and everything is fine.
- initialization from suspend is not good enough: my Asus stays in some text mode (80x25?), but shows garbage (possibly data from the desired console or graphics mode, since sometimes there are reactions correlated to actions) Switching tty or using `chvt` do not improve anything. NB: hibernating and booting solves this.
There are quite a few issues that needs to be addressed and code that needs to be refactored. I suggest you just dig in and get your hands dirty.
-Patrik