aee6f25e9c
After the recently added commit fe0f1e3bfdfe ("drm/i915: Shut down
displays gracefully on reboot"), the DSI panel on a Cherry Trail based
Predia Basic tablet would no longer properly light up after reboot.
I've managed to reproduce this without rebooting by doing:
chvt 3; echo 1 > /sys/class/graphics/fb0/blank;\
echo 0 > /sys/class/graphics/fb0/blank
Which rapidly turns the panel off and back on again.
The vlv_dsi.c code uses an intel_dsi_msleep() helper for the various delays
used for panel on/off, since starting with MIPI-sequences version >= 3 the
delays are already included inside the MIPI-sequences.
The problems exposed by the "Shut down displays gracefully on reboot"
change, show that using this helper for the panel_pwr_cycle_delay is
not the right thing to do. This has not been noticed until now because
normally the panel never is cycled off and directly on again in quick
succession.
Change the msleep for the panel_pwr_cycle_delay to a normal msleep()
call to avoid the panel staying black after a quick off + on cycle.
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Fixes: fe0f1e3bfdfe ("drm/i915: Shut down displays gracefully on reboot")
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/20210325114823.44922-1-hdegoede@redhat.com
(cherry picked from commit 2878b29fc25a0dac0e1c6c94177f07c7f94240f0)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.