On Thu, 18 Jun 2015, Edgardo Gho <edgardo.g@xxxxxxxxxxx> wrote: > Hi, > I have an AIO computer with a Pegatron BYT-T1 motherboard. Looks like a > cheap motherboard (using J1900). > It has an innolux 1366x768 panel (LVDS). The Motherboard also has LVDS > written on the connector. > I'm running kernel 4.0.5 on it (tinycore custom kernel) and xrandr > displays the port as eDP1 (not LVDS). > From what I can tell the panel is LVDS so I'm a little confused why the > kernel picks it up as eDP. The CPU is valleyview. This would be because BYT does not have LVDS, and apparently your motherboard has an eDP->LVDS adapter. > The problem I have is this: > When drm/i915 reads the EDID on eDP1, it gets a bunch of stuff > (including 1920x1080) and sets the resolution to that. > But the panel supports 1366x768 as max. That seems to be saved on VBT > since if I use vga=0x37f I get 1366x768 on fb. > But when drm reads 1920x1080 from EDID it sets that and the panel goes > into a weird mode (displaying colors) which I believe is a testing mode. > > I could try to fix the EDID, and also could generate one and use the > drm_kms_helper to pass a binary EDID. > What I don't understand is where is this EDID coming from. LVDS supports > EDID read? I don't see any i2c cable on the LVDS cable so I don't > understand how it can be reading the EDID. > Is the EDID saved on BIOS somehow? I assume the eDP->LVDS adapter responds to the EDID reads. The problem is, apparently it reports a preferred mode that the LVDS does not support, and our driver insists on using only the preferred mode for eDP. > I changed the code as suggested by this thread: > VLV: eDP: panel timings / resolution data from VBT, not via i2c from > eDP EDID > http://www.spinics.net/lists/intel-gfx/msg64312.html > > and I'm not letting edp read the EDID, so it fallbacks to VBT and > everything works great. > But I'm still not convinced that the EDID data comes from the LVDS Panel > (since it should have different info) > > Hope anyone can share some insights on what is going on. > Thanks BR, Jani. -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
