[ Upstream commit 74cde1a53368aed4f2b4b54bf7030437f64a534b ] On systems without HW-based collections (i.e. anything except GIC-500), we rely on firmware to perform the ITS save/restore. This doesn't really work, as although FW can properly save everything, it cannot fully restore the state of the command queue (the read-side is reset to the head of the queue). This results in the ITS consuming previously processed commands, potentially corrupting the state. Instead, let's always save the ITS state on suspend, disabling it in the process, and restore the full state on resume. This saves us from broken FW as long as it doesn't enable the ITS by itself (for which we can't do anything). This amounts to simply dropping the ITS_FLAGS_SAVE_SUSPEND_STATE. Signed-off-by: Xu Qiang <xuqiang36@huawei.com> [maz: added warning on resume, rewrote commit message] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201107104226.14282-1-xuqiang36@huawei.com Signed-off-by: Sasha Levin <sashal@kernel.org>
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.
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