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Since we use the audio component to transfer the ELD to the audio driver on hsw+ platforms there is no point in even programming the hardware ELD buffer. Stop doing so. The one slight caveat here is that this is not strictly legal according to the HDA spec. PD=1;ELD=0 is only documented as an intermediate state during modeset. But if there is no hardware that depends on that then I guess we're fine. Or we could perhaps set ELD=1 without actually programming the buffer? Note that the bspec sequence of PD=0;ELD=0 -> PD=1;ELD=0 -> PD=1;ELD=1 is also not strictly correct according to the HDA spec, as the only documented transition from PD=0;ELD=0 is straight to PD=1;ELD=1. Additionally on hsw/bdw the hardware buffer is tied in with the dedicated display HDA controller's power state, so currently we mostly fail at proramming the buffer anyway. When the HDA side is not sufficiently powered up the ELD address bits get stuck and the ELD data register accesses go nowhere. Cc: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com> Cc: Takashi Iwai <tiwai@suse.de> References: https://lore.kernel.org/intel-gfx/20221012104936.30911-1-ville.syrjala@linux.intel.com/ Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230124144628.4649-3-ville.syrjala@linux.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.