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James Clark
c45b2835e7
child_fwnode should be a read only property based on the DT or ACPI. If it's cleared on the parent device when a child is unloaded, then when the child is loaded again the connection won't be remade. child_dev should be cleared instead which signifies that the connection should be remade when the child_fwnode registers a new coresight_device. Similarly the reference count shouldn't be decremented as long as the parent device exists. The correct place to drop the reference is in coresight_release_platform_data() which is already done. Reproducible on Juno with the following steps: # load all coresight modules. $ cd /sys/bus/coresight/devices/ $ echo 1 > tmc_etr0/enable_sink $ echo 1 > etm0/enable_source # Works fine ^ $ echo 0 > etm0/enable_source $ rmmod coresight-funnel $ modprobe coresight-funnel $ echo 1 > etm0/enable_source -bash: echo: write error: Invalid argument Fixes:37ea1ffddf("coresight: Use fwnode handle instead of device names") Fixes:2af89ebacf("coresight: Clear the connection field properly") Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Signed-off-by: James Clark <james.clark@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20230425143542.2305069-2-james.clark@arm.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.