4.19-stable review patch. If anyone has any objections, please let me know.
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From: Paul Kocialkowski paul.kocialkowski@bootlin.com
commit 8fd3b90300bec541806dac271de2fd44e2e4e2d2 upstream.
Writeback connectors do not produce any on-screen output and require special care for use. Such connectors are hidden from enumeration in DRM resources by default, but they are still picked-up by fbdev. This makes rather little sense since fbdev is not really adapted for dealing with writeback.
Moreover, this is also a source of issues when userspace disables the CRTC (and associated plane) without detaching the CRTC from the connector (which is hidden by default). In this case, the connector is still using the CRTC, leading to am "enabled/connectors mismatch" and eventually the failure of the associated atomic commit. This situation happens with VC4 testing under IGT GPU Tools.
Filter out writeback connectors in the fbdev helper to solve this.
Signed-off-by: Paul Kocialkowski paul.kocialkowski@bootlin.com Reviewed-by: Boris Brezillon boris.brezillon@bootlin.com Reviewed-by: Maxime Ripard maxime.ripard@bootlin.com Tested-by: Maxime Ripard maxime.ripard@bootlin.com Fixes: 935774cd71fe ("drm: Add writeback connector type") Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch Link: https://patchwork.freedesktop.org/patch/msgid/20181115163248.21168-1-paul.ko... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/drm_fb_helper.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -200,6 +200,9 @@ int drm_fb_helper_single_add_all_connect mutex_lock(&fb_helper->lock); drm_connector_list_iter_begin(dev, &conn_iter); drm_for_each_connector_iter(connector, &conn_iter) { + if (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK) + continue; + ret = __drm_fb_helper_add_one_connector(fb_helper, connector); if (ret) goto fail;