<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - LVDS blank screen on GM45" href="https://bugs.freedesktop.org/show_bug.cgi?id=94825#c23">Comment # 23</a> on <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - LVDS blank screen on GM45" href="https://bugs.freedesktop.org/show_bug.cgi?id=94825">bug 94825</a> from <a class="email" href="mailto:ville.syrjala@linux.intel.com" title="Ville Syrjala <ville.syrjala@linux.intel.com>"> Ville Syrjala</a> <pre>(In reply to Rob Kramer from <a href="show_bug.cgi?id=94825#c22">comment #22</a>) > (In reply to Ville Syrjala from <a href="show_bug.cgi?id=94825#c21">comment #21</a>) > > I found something interesting in the opregion spec. Based on that I posted a > > few patches that could help here: > > <a href="https://lists.freedesktop.org/archives/intel-gfx/2016-April/091988.html">https://lists.freedesktop.org/archives/intel-gfx/2016-April/091988.html</a> > > > > Please test and report back. > > OK, reverted your previous _DDC patch, applied these three. The result is a > blank screen. I added some debug statements in your opregion.c patch: > > ret = swsci(dev, SWSCI_GBDA_PANEL_DETAILS, 0x0, &panel_details); > if (ret) > { > DRM_DEBUG_KMS ("Rob: return %d\n", ret); > return ret; > } > > DRM_DEBUG_KMS ("Rob: panel details 0x%x\n", panel_details); > > And in the log: > > [drm:intel_opregion_get_panel_type] Rob: panel details 0x21000 > > Which would mean panel 0x10 according to the spec in your mail, which would > be good if you'd started counting at 1 :) > > Next, I tried setting the mode to <a href="mailto:1366x768@73.8M">1366x768@73.8M</a> in the bios, and the output > changes to: > > [drm:intel_opregion_get_panel_type] Rob: panel details 0x20d00 > > That is off by one too, but is still good news since it follows the BIOS > setting.. Trying the obvious fix works: > > return ((panel_details >> 8) & 0xff) - 1; > > > "Bits [15:8] - Panel Type > > Bits contain the panel type user setting from CMOS > > 00h = Not Valid, use default Panel Type & Timings from VBT > > 01h - 0Fh = Panel Number" > > That would mean only 15 possible valid modes, right? But my BIOS has 16 in > its list already, and the correct mode happens to be the last one. > > [No log attached, because nothing further of interest] Thanks for testing. I found another version of the spec that says panel type 16 is still valid. I posted new versions of patches 1 and 3. Please double check that they work correctly.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> </ul> </body> </html>