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Lucas Stach authored
The read is taking a considerable amount of time (about 50us on this machine). The register does not ever hold anything other than the ring ID that is updated in this exact function, so there is no need for the read modify write cycle. This chops off a big chunk of the time spent in hardirq disabled context, as this function is called multiple times in the interrupt handler. With this change applied radeon won't show up in the list of the worst IRQ latency offenders anymore, where it was a regular before. Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Lucas Stach <dev@lynxeye.de> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Cc: stable@vger.kernel.org
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