<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - LG 31MU97 monitor native resolution is 4096x2160, but highest mode found is 3840x2160" href="https://bugs.freedesktop.org/show_bug.cgi?id=108081#c14">Comment # 14</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - LG 31MU97 monitor native resolution is 4096x2160, but highest mode found is 3840x2160" href="https://bugs.freedesktop.org/show_bug.cgi?id=108081">bug 108081</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 Brian Vincent from <a href="show_bug.cgi?id=108081#c13">comment #13</a>) > Created <a href="attachment.cgi?id=141777" name="attach_141777" title="31mu97 EDID when attaching to amdgpu">attachment 141777</a> <a href="attachment.cgi?id=141777&action=edit" title="31mu97 EDID when attaching to amdgpu">[details]</a> > 31mu97 EDID when attaching to amdgpu > > When I attach this same monitor to my other computer with an AMDGPU, I get > the attached EDID and the mode 4096x2160 is actually found. So this is > probably what the proper EDID is supposed to look like, right? Interesting. The extra block is the DisplayID as I suspected. amdgpu uses the same MST sideband code that i915 uses, so can't immediately see how it could get different results. Looking at the earlier i915 logs I see a bunch of [ 6.899169] [drm:drm_dp_mst_hpd_irq [drm_kms_helper]] Got NAK reply: req 0x22, reason 0x09, nak data 0x40 Those are REMOTE_I2C_READ/I2C_NAK replies with NAK_data 0x40 (which the spec doesn't say what it means). Could be the remaining amount of data or something I suppose. Can you grab similar logs from amdgpu to see if we get any of those errors there? The only clear difference I see with amdgpu vs. i915 is the number of ESI registers we read when processing the hpd irq. The following diff should make i915 match amdgpu behaviour: diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 8e465095fe06..3f94dcc96f22 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -43,7 +43,7 @@ #include <drm/i915_drm.h> #include "i915_drv.h" -#define DP_DPRX_ESI_LEN 14 +#define DP_DPRX_ESI_LEN 4 /* Compliance test status bits */ #define INTEL_DP_RESOLUTION_SHIFT_MASK 0</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> <li>You are on the CC list for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>