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e028d7a423
We have experienced timeout issues when going through the sequence to
access C20 SRAM registers. Experimentation showed that bumping the
message bus timer threshold helped on getting display Type-C connection
on the C20 PHY to work.
While the timeout is still under investigation with the HW team, having
logic to allow forward progress (with the proper warnings) seems useful.
Thus, let's bump the threshold when a timeout is detected.
The bumped value of 0x200 pclk cycles was somewhat arbitrary - 2x the
default value. That value was successfully tested on real hardware that
was displaying timeouts otherwise.
v2:
- Reword commit message to indicate that access to C20 SRAM registers
is not direct. (Radhakrishna)
- Prefer not to use REG_FIELD_PREP() in intel_cx0_phy.c.
(Radhakrishna)
- Simplify intel_cx0_bus_check_and_bump_timer() to use a fixed bumped
value instead of progressively increasing the threshold. (Mika)
BSpec: 65156
Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Cc: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230830121524.15101-1-gustavo.sousa@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.