2f09395839
At least Bay Trail (BYT) and Cherry Trail (CHT) devices can use 1 of 2 different PWM controllers for controlling the LCD's backlight brightness. Either the one integrated into the PMIC or the one integrated into the SoC (the 1st LPSS PWM controller). So far in the LPSS code on BYT we have skipped registering the LPSS PWM controller "pwm_backlight" lookup entry when a Crystal Cove PMIC is present, assuming that in this case the PMIC PWM controller will be used. On CHT we have been relying on only 1 of the 2 PWM controllers being enabled in the DSDT at the same time; and always registered the lookup. So far this has been working, but the correct way to determine which PWM controller needs to be used is by checking a bit in the VBT table and recently I've learned about 2 different BYT devices: Point of View MOBII TAB-P800W Acer Switch 10 SW5-012 Which use a Crystal Cove PMIC, yet the LCD is connected to the SoC/LPSS PWM controller (and the VBT correctly indicates this), so here our old heuristics fail. Since only the i915 driver has access to the VBT, this commit renames the "pwm_backlight" lookup entries for the Crystal Cove PMIC's PWM controller to "pwm_pmic_backlight" so that the i915 driver can do a pwm_get() for the right controller depending on the VBT bit, instead of the i915 driver relying on a "pwm_backlight" lookup getting registered which magically points to the right controller. Acked-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Acked-by: Lee Jones <lee.jones@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20191216202906.1662893-3-hdegoede@redhat.com |
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| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
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.