Russell, On Wed, Jun 17, 2015 at 4:30 PM, Russell King - ARM Linux <linux at arm.linux.org.uk> wrote: > On Wed, Jun 17, 2015 at 04:14:07PM -0700, Doug Anderson wrote: >> If you plug in a DVI monitor to your HDMI port, you need to filter out >> clocks > 165MHz. That's because 165MHz is the maximum clock rate that >> we can run single-link DVI at. >> >> If you want to run high resolutions to DVI, you'd need some type of an >> active adapter that pretended that it was HDMI, interpreted the >> signal, and produced a new dual link DVI signal at a lower clock rate. >> >> Signed-off-by: Doug Anderson <dianders at chromium.org> >> --- >> Note: this patch was tested against a 3.14 kernel with backports. It >> was only compile tested against linuxnext, but the code is >> sufficiently similar that I'm convinced it will work there. > > Really? I have to wonder what your testing was... > > hdmi->vic = drm_match_cea_mode(mode); > > if (!hdmi->vic) { > dev_dbg(hdmi->dev, "Non-CEA mode used in HDMI\n"); > hdmi->hdmi_data.video_mode.mdvi = true; > } else { > dev_dbg(hdmi->dev, "CEA mode used vic=%d\n", hdmi->vic); > hdmi->hdmi_data.video_mode.mdvi = false; > } > > mdvi indicates whether the _currently set mode_ is a CEA mode or not (imho, > it's mis-named). It doesn't indicate whether we have a HDMI display device > or a DVI display device connected, which seems to be what you want to use > it for below. > > To sort that, what you need to do is detect a HDMI display device using > drm_detect_hdmi_monitor() on the EDID received from the device before > parsing the modes, and save that value in a dw_hdmi struct member, and > I'd suggest that it's a top-level struct member, not buried in 'hdmi_data' > or 'video_mode'.
OK, so clearly my patch won't work against mainline. I guess it's a good thing that I pointed out that it was only tested locally (would have been better to test against mainline, but I don't think that's so easy since there are several unlanded patches in mainline for Rockchip). As pointed out by others at <http://crosreview.com/278255>, locally our kernel has a slightly older version of <https://lkml.org/lkml/2015/2/28/291>, which would change mdvi to be as needed. ...so I guess my change is blocked on someone reviewing/landing that series. If that series is rejected (or is changed sufficiently so that mdvi no longer is set via drm_detect_hdmi_monitor() then my patch will need to be re-spun. -Doug