On Sun, Dec 09, 2012 at 07:37:40PM -0200, Paulo Zanoni wrote: > Hi > > 2012/12/8 Damien Lespiau <damien.lespiau at intel.com>: > > On Sat, Dec 1, 2012 at 2:04 PM, Paulo Zanoni <przanoni at gmail.com> wrote: > >> From: Paulo Zanoni <paulo.r.zanoni at intel.com> > >> > >> If we fail to set the bit when needed we get some nice FDI link > >> training failures (AKA "black screen on VGA output"). > >> > >> While we don't really know how to properly choose whether we need to > >> set the bit or not (VBT?), just read the initial value set by the BIOS > >> and store it for later usage. > >> > >> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com> > > > > Sad that we did not catch that before. It's not just the polarity > > (support for exchanging the - and + wires on a differential pair), but > > also the FDI lane reversal (0 becomes 3, 1 becomes 2) setting that we > > need to preserve. There's a fused bit for the DMI lane reversal and > > FDI defaults to following that DMI lane reversal configuration, but we > > also have a bit to override that behaviour in the FDI RX register, we > > need to preserve this bit as well. > > They're different problems and require different patches. This one > fixes the "FDI RX polarity" problem, not "lane reversal". Picked up for -fixes (together with patch 1), thanks for the patch. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
