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authorMing Lei <ming.lei@canonical.com>2011-08-31 00:03:13 +0800
committerAndrey Konovalov <andrey.konovalov@linaro.org>2012-02-14 23:03:46 +0400
commit7f2be4a1c8181de24da244673b16ee98926b4a7e (patch)
treeecbacdafd369e8e1869aa8fdf876c70e8d0812a4 /arch
parentd65b4e98d7ea3038b767b70fe8be959b2913f16d (diff)
usb: ehci: make HC see up-to-date qh/qtd descriptor ASAP
This patch introduces the helper of ehci_sync_mem to flush qtd/qh into memory immediately on some ARM, so that HC can see the up-to-date qtd/qh descriptor asap. This patch fixs one performance bug on ARM Cortex A9 dual core platform, which has been reported on quite a few ARM machines (OMAP4, Tegra 2, snowball...), see details from link of https://bugs.launchpad.net/bugs/709245. The patch has been tested ok on OMAP4 panda A1 board, and the performance of 'dd' over usb mass storage can be increased from 4~5MB/sec to 14~16MB/sec after applying this patch. Cc: Russell King <linux@arm.linux.org.uk> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Diffstat (limited to 'arch')
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