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When a read transaction completes, one of several things will happen: a new transfer is started by the driver, a new transfer request is raised by the Cuda (i.e. TREQ asserted), or both happen at once. When both happen at once, there is a race condition between the TREQ test in the read_done state and the same test in cuda_start(). Moreover, the former test uses a stale TREQ value. Theoretically, this can result in the undesirable outcome that the interrupt handler completes with the state machine 'idle' when it should instead start the next transaction. Avoid this race by calling cuda_start() first and then confirming that it succeeded. If not, test the current TREQ value before entering the 'reading' state. Tested-by: Stan Johnson <userm57@yahoo.com> Signed-off-by: Finn Thain <fthain@telegraphics.com.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.