Hello Nico Huber, Patrick Georgi, Martin Roth,
I'd like you to reexamine a change. Please visit
https://review.coreboot.org/c/libgfxinit/+/41343
to look at the new patch set (#8).
Change subject: haswell: Make VGA on FDI work ......................................................................
haswell: Make VGA on FDI work
Attempting to light up a 1920x1080 monitor through VGA with libgfxinit on Haswell would either hang the system or show garbage on the monitor. This was due to two different problems around FDI initialization code.
The system would only hang if libgfxinit was the first program to light up a monitor on VGA. This is because no one had performed the required FDI mPHY initialization that is described on the Haswell graphics PRMs. Add it to libgfxinit alongside some code to disable bending CLKOUT_DP.
Even with the FDI mPHY initialization in place, the garbage would still be present on the VGA monitor. Digital interfaces were not affected. By carefully dumping and comparing the display registers of a good and a bad case, it was determinted that the fault was due to a mismatched link width for FDI. The FDI link between the iGPU and the Lynxpoint PCH can operate in either x1 or x2 width, depending on the bandwidth needs of the monitor on the PCH's VGA port. To drive a 1920x1080 VGA monitor, it is necessary to use both FDI lanes. Moreover, both ends of the link need to be configured to use the same link width. However, this was not the case, because one of the link ends programmed the link width for DP unconditionally, so one end of FDI would always end up using x1 width.
After fixing both issues, gfx_test is able to light up a 1920x1080 VGA monitor on the Asrock B85M Pro4 successfully, even after a S3 resume.
Change-Id: Ieabe3b7f947be2ef488ddb57bfeae85fa055d360 Signed-off-by: Angel Pons th3fanbus@gmail.com --- M common/haswell/Makefile.inc A common/haswell/hw-gfx-gma-pch-lynxpoint.adb A common/haswell/hw-gfx-gma-pch-lynxpoint.ads M common/haswell/hw-gfx-gma-power_and_clocks_haswell.adb M common/hw-gfx-gma-pch-sideband.adb M common/hw-gfx-gma-pch-sideband.ads M common/hw-gfx-gma-transcoder.adb 7 files changed, 266 insertions(+), 5 deletions(-)
git pull ssh://review.coreboot.org:29418/libgfxinit refs/changes/43/41343/8