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Some Synaptics MST branch devices have a problem decompressing a stream with a compressed link-bpp higher than 12, if the pixel clock is higher than ~50 % of the maximum throughput capability reported by the branch device. The screen remains blank, or for some - mostly black content - gets enabled, but may stil have jitter artifacts. At least the following docking stations are affected, based on testing both with any Intel devices or the UCD-500 reference device as a source: - DELL WD19DCS, DELL WD19TB3, DELL WD22TB4 - ThinkPad 40AN - HP G2 At least the following docking stations are free from this problem, based on tests with a source/sink/mode etc. configuration matching the test cases used above: - DELL Dual Charge HD22Q, DELL WD25TB5 - ThinkPad 40B0 - Anker 565 All the affected devices have an older version of the Synaptics MST branch device (Panamera), whereas all the non-affected docking stations have a newer branch device (at least Synaptics Panamera with a higher HW revision number and Synaptics Cayenne models). Add the required quirk entries accordingly. The quirk will be handled by the i915/xe drivers in a follow-up change. The latest firmware version of the Synaptics branch device for all the affected devices tested above is 5.7 (as reported at DPCD address 0x50a/0x50b). For the DELL devices this corresponds to the latest 01.00.14.01.A03 firmware package version of the docking station. v2: - Document the DP_DPCD_QUIRK_DSC_THROUGHPUT_BPP_LIMIT enum. - Describe the quirk in more detail in the dpcd_quirk_list. v3: - s/Panarema/Panamera in the commit log. Cc: dri-devel@lists.freedesktop.org Reported-by: Vidya Srinivas <vidya.srinivas@intel.com> Reported-and-tested-by: Swati Sharma <swati2.sharma@intel.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Signed-off-by: Imre Deak <imre.deak@intel.com> Link: https://lore.kernel.org/r/20250930182450.563016-2-imre.deak@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 reStructuredText 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.