Asus T100 has a mipi dsi panel, and we don't yet have the proper support for that merged. Hopefully that will get adressed in 3.16. See https://bugzilla.kernel.org/show_bug.cgi?id=74381 for the overall progress. -Daniel On Sun, May 11, 2014 at 6:27 AM, Jon Pry <jonpry@xxxxxxxxx> wrote: > Hi, > > I'm trying to work out some bugs on Asus T100TA which is Baytrail-T > platform. Current code in use is 3.15_rc4. In general I have been > having problems with the backlight control. For some reason the kernel > is detecting the panel as a VGA device and intel_crt.c does not load > intel_backlight, so I hacked something together real quick and ended > up getting something that actual changes PWM registers, but this had > no effect on actual screen brightness. > > Without any real solid theory as to why PWM is not doing anything. > I started wondering why exactly the kernel thinks the panel is VGA > since it is kind of unlikely the panel is analog especially > considering Baytrail-T does not have any analog interfaces. So I > nabbed the VBT to take a look. > > Whole thing is here if your interested http://pastebin.com/crht1nDU > > Pretty sure the relevant portion is: > > EFP device info: > Device type: 0x1400 (unknown) > Port: 0x15 (unknown) > DDC pin: 0x04 > Dock port: 0x00 (N/A) > HDMI compatible? No > Info: HDMI certified > Aux channel: 0x00 > Dongle detect: 0x00 > > The VBT does include tables for LVDS/eDP operation of the panel. It > seems just the device type is fubar. So my questions are, why is the > type screwed up? What would windows driver do upon seeing that, and > what is the best way to override it in the kernel? > > The practical impact here I think will be during sleep. As taking down > the eDP link is unlikely to work so long as driver thinks it is a CRT. > > Also I notice that the backlight block contains these values: > > I2C slave addr: 0x58 > I2C command: 0xaa > > Which are not used in the linux driver. Is this something the windows > driver actually does? Any plans to implement i2c backlight control in > i915? > > Regards, > > Jon Pry > jonpry@xxxxxxxxx > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
