From: Fenghua Yu Date: Wed, 18 Feb 2009 23:54:33 +0000 (-0800) Subject: iwlwifi: dma mapping read and write changes X-Git-Tag: v2.6.30-rc1~662^2~460^2~63 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=96891ceedaeaac95aa5b9dba5e68a8e77d541e78;p=pandora-kernel.git iwlwifi: dma mapping read and write changes When iwlwifi runs on IOMMU, IOMMU generates a lot of PTE write faults because PTE write bit is not set on some of PTE's. This is because iwlwifi driver calls DMA mapping with PCI_DMA_TODEVICE which is read only in mapping PTE. But iwlwifi device actually writes to the mapped page to update its contents. This issue is not exposed in swiotlb. But VT-d hardware can capture this fault and stop the fault transaction. The iwl TX command contains a scratch field that is updated by uCode to indicate retry counts. For 5000 series the patch is required also for regular frames, but this patch does not differenciate. Signed-off-by: Fenghua Yu Acked-by: Tomas Winkler Signed-off-by: Reinette Chatre Signed-off-by: John W. Linville --- Reading git-diff-tree failed