57cb54e53b
Henning Kühn reported that the discrete AMD GPU on his hybrid graphics
laptop no longer runtime-suspends due to the recent commit
07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller").
The root cause is that the HDMI codec on AMD GPU doesn't support
CLKSTOP and EPSS, which are currently mandatory for powering down the
HD-audio link at runtime suspend. Because the HD-audio link is still
up, HD-audio controller driver blocks the transition to D3.
For addressing the regression, this patch adds a new flag to indicate
the forced link-down, and sets it for AMD HDMI codecs appropriately
in the codec driver.
Fixes: 07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106957
Reported-by: Lukas Wunner <lukas@wunner.de>
Reported-and-tested-by: Henning Kühn <prg@cooco.de>
Cc: <stable@vger.kernel.org> # v4.17+
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.