The intention of using video=<connector>:<mode: is primarily to select the user's preferred resolution at startup. Currently we always create a GTF mode irrespective of whether the monitor has a native mode at the desired resolution. This has the issue that we may then select the fake GTF mode rather the native mode during fb_helper->inital_config() and so on a non-GTF monitor we then end up with a loss of signal. Oops. This invalid fake mode would also be exported to userspace, who potentially may make the same mistake.
To avoid this issue, we filter out the added command line mode if we detect the desired resolution (and clock if specified) amongst the probed modes. This fixes the immediate problem of adding a duplicate mode, but perhaps more generically we should avoid adding a GTF mode if the monitor has an EDID that is not GTF-compatible...
A second issue sneaked into this patch is to add the cmdline mode mode ahead of the absolute fallback 1024x768 mode. That is if the user has specified a mode that we create as a fallback, we do not need to add a second unused fallback mode.
Fixes regression from
commit eaf99c749d43ae74ac7ffece5512f3c73f01dfd2 Author: Chris Wilson chris@chris-wilson.co.uk Date: Wed Aug 6 10:08:32 2014 +0200
drm: Perform cmdline mode parsing during connector initialisation
that breaks HDMI output on BeagleBone Black with LG TV (model 19LS4R-ZA).
Reported-by: Radek Dostál rd@radekdostal.com Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Radek Dostál rd@radekdostal.com Cc: Jesse Barnes jbarnes@virtuousgeek.org Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: dri-devel@lists.freedesktop.org Cc: Julia Lemire jlemire@matrox.com Cc: Dave Airlie airlied@redhat.com Cc: stable@vger.kernel.org --- drivers/gpu/drm/drm_probe_helper.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c index 63503879a676..b4b61cc4168e 100644 --- a/drivers/gpu/drm/drm_probe_helper.c +++ b/drivers/gpu/drm/drm_probe_helper.c @@ -79,16 +79,33 @@ drm_mode_validate_flag(const struct drm_display_mode *mode,
static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector) { + struct drm_cmdline_mode *cmdline_mode; struct drm_display_mode *mode;
- if (!connector->cmdline_mode.specified) + cmdline_mode = &connector->cmdline_mode; + if (!cmdline_mode->specified) return 0;
mode = drm_mode_create_from_cmdline_mode(connector->dev, - &connector->cmdline_mode); + cmdline_mode); if (mode == NULL) return 0;
+ /* Only add a GTF mode if we find no matching probed modes */ + list_for_each_entry(mode, &connector->probed_modes, head) { + if (mode->hdisplay != cmdline_mode->xres || + mode->vdisplay != cmdline_mode->yres) + continue; + + if (cmdline_mode->refresh_specified) { + if (mode->vrefresh != cmdline_mode->refresh) + continue; + } + + mode->status = MODE_BAD; + break; + } + drm_mode_probed_add(connector, mode); return 1; } @@ -179,9 +196,9 @@ static int drm_helper_probe_single_connector_modes_merge_bits(struct drm_connect count = (*connector_funcs->get_modes)(connector); }
+ count += drm_helper_probe_add_cmdline_mode(connector); if (count == 0 && connector->status == connector_status_connected) count = drm_add_modes_noedid(connector, 1024, 768); - count += drm_helper_probe_add_cmdline_mode(connector); if (count == 0) goto prune;
@@ -195,7 +212,8 @@ static int drm_helper_probe_single_connector_modes_merge_bits(struct drm_connect mode_flags |= DRM_MODE_FLAG_3D_MASK;
list_for_each_entry(mode, &connector->modes, head) { - mode->status = drm_mode_validate_basic(mode); + if (mode->status != MODE_BAD) + mode->status = drm_mode_validate_basic(mode);
if (mode->status == MODE_OK) mode->status = drm_mode_validate_size(mode, maxX, maxY);