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Link training fails with: Link training timeout waiting for LT_LOOPDONE! main link enable error: -110 This is caused by too tight timeouts, which were changed recently inaa92213f38("drm/bridge: tc358767: Simplify polling in tc_link_training()"). With a quick glance, the commit does not change the timeouts. However, the method of delaying/sleeping is different, and as the timeout in the previous implementation was not explicit, the new version in practice has much tighter timeout. The same change was made to other parts in the driver, but the link training timeout is the only one I have seen causing issues. Nevertheless, 1 us sleep is not very sane, and the timeouts look pretty tight, so lets fix all the timeouts. One exception was the aux busy poll, where the poll sleep was much longer than necessary (or optimal). I measured the times on my setup, and now the sleep times are set to such values that they result in multiple loops, but not too many (say, 5-10 loops). The timeouts were all increased to 100ms, which should be more than enough for all of these, but in case of bad errors, shouldn't stop the driver as multi-second timeouts could do. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com> Fixes:aa92213f38("drm/bridge: tc358767: Simplify polling in tc_link_training()") Tested-by: Andrey Smirnov <andrew.smirnov@gmail.com> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191209082707.24531-1-tomi.valkeinen@ti.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.