Hi John,
On 14 February 2017 at 19:25, John Stultz <john.stultz@linaro.org> wrote:
+static enum drm_mode_status
+drm_connector_check_crtc_modes(struct drm_connector *connector,
+ struct drm_display_mode *mode)
+{
+ struct drm_device *dev = connector->dev;
+ const struct drm_crtc_helper_funcs *crtc_funcs;
+ struct drm_crtc *c;
+
+ if (mode->status != MODE_OK)
+ return mode->status;
+
+ /* Check all the crtcs on a connector to make sure the mode is valid */
+ drm_for_each_crtc(c, dev) {
+ crtc_funcs = c->helper_private;
+ if (crtc_funcs && crtc_funcs->mode_valid)
+ mode->status = crtc_funcs->mode_valid(c, mode);
+ if (mode->status != MODE_OK)
+ break;
+ }
+ return mode->status;
+}
Hm, that's unfortunate: it limits the mode list for every connector,
to those which are supported by every single CRTC. So if you have one
CRTC serving low-res LVDS, and another serving higher-res HDMI,
suddenly you can't get bigger modes on HDMI. The idea seems sound
enough, but a little more nuance might be good ...