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由 Alan Stern 提交于
This patch (as1661) fixes a rather obscure bug in ehci-hcd. In a couple of places, the driver compares the DMA address stored in a QH's overlay region with the address of a particular qTD, in order to see whether that qTD is the one currently being processed by the hardware. (If it is then the status in the QH's overlay region is more up-to-date than the status in the qTD, and if it isn't then the overlay's value needs to be adjusted when the QH is added back to the active schedule.) However, DMA address in the overlay region isn't always valid. It sometimes will contain a stale value, which may happen by coincidence to be equal to a qTD's DMA address. Instead of checking the DMA address, we should check whether the overlay region is active and valid. The patch tests the ACTIVE bit in the overlay, and clears this bit when the overlay becomes invalid (which happens when the currently-executing URB is unlinked). This is the second part of a fix for the regression reported at: https://bugs.launchpad.net/bugs/1088733Signed-off-by: NAlan Stern <stern@rowland.harvard.edu> Reported-by: NJoseph Salisbury <joseph.salisbury@canonical.com> Reported-and-tested-by: NStephen Thirlwall <sdt@dr.com> CC: <stable@vger.kernel.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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