Commit 25b4620ee822 ("drm/i915/dsi: Skip delays for v3 VBTs in vid-mode") added an intel_dsi_msleep() helper which skips sleeping if the MIPI-sequences have a version of 3 or newer and the panel is in vid-mode; and it moved a bunch of msleep-s over to this new helper. This was based on my reading of the big comment around line 730 which starts with "Panel enable/disable sequences from the VBT spec.", where the "v3 video mode seq" column does not have any wait t# entries. Given that this code has been used on a lot of different devices without issues until now, it seems that my interpretation of the spec here is mostly correct. But now I have encountered one device, an Acer Aspire Switch 10 E SW3-016, where the panel will not light up unless we do actually honor the panel_on_delay after exexuting the MIPI_SEQ_PANEL_ON sequence. What seems to set this model apart is that it is lacking a MIPI_SEQ_DEASSERT_RESET sequence, which is where the power-on delay usually happens. Fix the panel not lighting up on this model by using an unconditional msleep(panel_on_delay) instead of intel_dsi_msleep() when there is no MIPI_SEQ_DEASSERT_RESET sequence. Fixes: 25b4620ee822 ("drm/i915/dsi: Skip delays for v3 VBTs in vid-mode") Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> --- drivers/gpu/drm/i915/display/vlv_dsi.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/display/vlv_dsi.c b/drivers/gpu/drm/i915/display/vlv_dsi.c index 194c239ab6b1..ef673277b36d 100644 --- a/drivers/gpu/drm/i915/display/vlv_dsi.c +++ b/drivers/gpu/drm/i915/display/vlv_dsi.c @@ -816,10 +816,14 @@ static void intel_dsi_pre_enable(struct intel_atomic_state *state, intel_dsi_prepare(encoder, pipe_config); intel_dsi_vbt_exec_sequence(intel_dsi, MIPI_SEQ_POWER_ON); - intel_dsi_msleep(intel_dsi, intel_dsi->panel_on_delay); - /* Deassert reset */ - intel_dsi_vbt_exec_sequence(intel_dsi, MIPI_SEQ_DEASSERT_RESET); + if (dev_priv->vbt.dsi.sequence[MIPI_SEQ_DEASSERT_RESET]) { + intel_dsi_msleep(intel_dsi, intel_dsi->panel_on_delay); + /* Deassert reset */ + intel_dsi_vbt_exec_sequence(intel_dsi, MIPI_SEQ_DEASSERT_RESET); + } else { + msleep(intel_dsi->panel_on_delay); + } if (IS_GEMINILAKE(dev_priv)) { glk_cold_boot = glk_dsi_enable_io(encoder); -- 2.28.0 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel