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Now that we've added the `off-on-delay-us` for the touchpanel regulator, we can see that we're actually hitting that delay at bootup. I saw about 200 ms of delay. Let's avoid that delay by starting the regulator on. We'll only do this for eDP devices for the time being. NOTE: we _won't_ do this for homestar. Homestar's panel really likes to be power cycled. It's why the Linux driver for this panel has a pm_runtime_put_sync_suspend() when the panel is being unprepared but the normal panel-edp driver doesn't. It's also why this hardware has a separate power rail for eDP vs. touchscreen, unlike all the other trogdor boards. We won't start homestar's regulator on. While this could mean a slight delay on homestar, it is probably a _correct_ delay. The bootloader might have left the regulator on (it does so in dev and recovery modes), so if we turned the regulator off at probe time and we actually hit the delay then we were probably violating T12 in the panel spec. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Signed-off-by: Bjorn Andersson <andersson@kernel.org> Link: https://lore.kernel.org/r/20221209091234.v3.3.I7050a61ba3a48e44b86053f265265b5e3c0cee31@changeid
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.