<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - Linux: REGRESSION: drm: cmdline EDID override mechanisms broken since 4.15" href="https://bugs.freedesktop.org/show_bug.cgi?id=107583#c23">Comment # 23</a> on <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - Linux: REGRESSION: drm: cmdline EDID override mechanisms broken since 4.15" href="https://bugs.freedesktop.org/show_bug.cgi?id=107583">bug 107583</a> from <a class="email" href="mailto:jani.nikula@intel.com" title="Jani Nikula <jani.nikula@intel.com>"> Jani Nikula</a> <pre>(In reply to harish.chegondi from <a href="show_bug.cgi?id=107583#c19">comment #19</a>) > (In reply to Jani Nikula from <a href="show_bug.cgi?id=107583#c18">comment #18</a>) > > > > I think there's a conflicting set of valid requirements here, and the only > > way to preserve functionality for all cases is to add another level of > > connector force probe, which skips DDC probe in case of override/firmware > > EDID. > > If I understand Jani's comment correctly, in drm_get_edid(), DDC probe > should be skipped if the connector force is unspecified and EDID has to be > overridden. When I analyzed the code further, I felt the check that does DDC > probe if connector force is unspecified can be eliminated and will also fix > this bug. I mentioned my proposed change below. I also submitted this change > to trybot and it was successful. > > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -1724,9 +1724,6 @@ struct edid *drm_get_edid(struct drm_connector > *connector, > if (connector->force == DRM_FORCE_OFF) > return NULL; > > - if (connector->force == DRM_FORCE_UNSPECIFIED && !drm_probe_ddc(adapter)) > - return NULL; > - > edid = drm_do_get_edid(connector, drm_do_probe_ddc_edid, adapter); > if (edid) > drm_get_displayid(connector, edid); This loses the ability to use DDC probe for detecting display, leading to excessive failures in drm_do_get_edid() if the display isn't there.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> </ul> </body> </html>