From: Hans de Goede hdegoede@redhat.com
commit 00cb645fd7e29bdd20967cd20fa8f77bcdf422f9 upstream.
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@redhat.com Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20201118124058.26021-1-hdegoed... (cherry picked from commit 6fdb335f1c9c0845b50625de1624d8445c4c4a07) Signed-off-by: Jani Nikula jani.nikula@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/i915/display/vlv_dsi.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
--- a/drivers/gpu/drm/i915/display/vlv_dsi.c +++ b/drivers/gpu/drm/i915/display/vlv_dsi.c @@ -797,10 +797,20 @@ static void intel_dsi_pre_enable(struct if (intel_dsi->gpio_panel) gpiod_set_value_cansleep(intel_dsi->gpio_panel, 1); 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); + /* + * Give the panel time to power-on and then deassert its reset. + * Depending on the VBT MIPI sequences version the deassert-seq + * may contain the necessary delay, intel_dsi_msleep() will skip + * the delay in that case. If there is no deassert-seq, then an + * unconditional msleep is used to give the panel time to power-on. + */ + if (dev_priv->vbt.dsi.sequence[MIPI_SEQ_DEASSERT_RESET]) { + intel_dsi_msleep(intel_dsi, intel_dsi->panel_on_delay); + 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);