On some devices only MIPI PORT C is used, in this case checking the MIPI PORT A CTRL AFE_LATCHOUT bit (there is no such bit for PORT C on VLV/CHT) will result in false positive "DSI LP not going Low" errors as this checks the PORT A clk status.
In case both ports are used we have already checked the AFE_LATCHOUT bit when going through the for_each_dsi_port() loop for PORT A and checking the same bit again for PORT C is a no-op. BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=97061 Signed-off-by: Hans de Goede <hdego...@redhat.com> --- drivers/gpu/drm/i915/intel_dsi.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c index 1fcce2c..185b8eb 100644 --- a/drivers/gpu/drm/i915/intel_dsi.c +++ b/drivers/gpu/drm/i915/intel_dsi.c @@ -458,10 +458,12 @@ static void intel_dsi_clear_device_ready(struct intel_encoder *encoder) ULPS_STATE_ENTER); usleep_range(2000, 2500); - /* Wait till Clock lanes are in LP-00 state for MIPI Port A - * only. MIPI Port C has no similar bit for checking + /* + * On VLV/CHV, wait till Clock lanes are in LP-00 state for MIPI + * Port A only. MIPI Port C has no similar bit for checking. */ - if (intel_wait_for_register(dev_priv, + if ((IS_GEN9_LP(dev_priv) || port == PORT_A) && + intel_wait_for_register(dev_priv, port_ctrl, AFE_LATCHOUT, 0, 30)) DRM_ERROR("DSI LP not going Low\n"); -- 2.9.3 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
