Ira Snyder 6c15d7afbb carma-fpga: fix race between data dumping and DMA callback ... When the system is under heavy load, we occasionally saw a problem where the system would get a legitimate interrupt when they should be disabled. This was caused by the data_dma_cb() DMA callback unconditionally re-enabling FPGA interrupts even when data dumping is disabled. When data dumping was re-enabled, the irq handler would fire while a DMA was in progress. The "BUG_ON(priv->inflight != NULL);" during the second invocation of the DMA callback caused the system to crash. To fix the issue, the priv->enabled boolean is moved under the protection of the priv->lock spinlock. The DMA callback checks the boolean to know whether to re-enable FPGA interrupts before it returns. Now that it is fixed, the driver keeps FPGA interrupts disabled when it expects that they are disabled, fixing the bug. Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>		2012-02-27 11:33:59 +11:00
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carma-fpga-program.c	Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma	2012-01-17 18:40:24 -08:00
carma-fpga.c	carma-fpga: fix race between data dumping and DMA callback	2012-02-27 11:33:59 +11:00
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