On Fri, 28 Aug 2026, Thadeu Lima de Souza Cascardo <[email protected]> wrote: > On Wed, Aug 19, 2026 at 03:07:40PM -0400, Mark Yacoub wrote: >> Writeback and virtual connectors (e.g. DRM_MODE_CONNECTOR_WRITEBACK and >> DRM_MODE_CONNECTOR_VIRTUAL) do not represent physical display sinks and >> cannot be modeset using standard CRTC / atomic commit operations without >> configuring a writeback output framebuffer (WRITEBACK_FB_ID). >> >> On drivers such as MSM, writeback connectors (e.g. Virtual-1, Virtual-2) >> report connected status with virtual modes. When generic KMS tests iterate >> over connected outputs via for_each_connected_output() or during initial >> display setup in igt_display_init(), attempting standard modesets on these >> connectors causes failures (-EINVAL) before test execution can begin. >> >> Exclude DRM_MODE_CONNECTOR_WRITEBACK and DRM_MODE_CONNECTOR_VIRTUAL in >> igt_output_is_connected() so generic KMS tests only target standard >> physical display outputs, while dedicated writeback tests can continue to >> iterate all outputs explicitly via for_each_output(). >> >> Signed-off-by: Mark Yacoub <[email protected]> >> --- >> lib/igt_kms.h | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/lib/igt_kms.h b/lib/igt_kms.h >> index 521a03c01..8d4d14847 100644 >> --- a/lib/igt_kms.h >> +++ b/lib/igt_kms.h >> @@ -668,6 +668,10 @@ static inline bool igt_output_is_connected(igt_output_t >> *output) >> !output->config.connector->count_modes) >> return false; >> >> + if (output->config.connector->connector_type == >> DRM_MODE_CONNECTOR_WRITEBACK || >> + output->config.connector->connector_type == >> DRM_MODE_CONNECTOR_VIRTUAL) >> + return false; >> + >> if (output->config.connector->connection == DRM_MODE_CONNECTED) >> return true; >> >> -- >> 2.55.0.737.g08866a6d13-goog >> > > This makes a lot of tests (including a lot of kms_*) be skipped on VKMS. Is > that correct?
I think the commit overlooked the fact that VKMS has virtual connectors only. Probably needs a revert and a return to the drawing board. Also, Someone(tm) should run CI with VKMS and IGT. Never tried myself, but shouldn't that be possible in user-mode Linux? BR, Jani. -- Jani Nikula, Intel
