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authorAlan Stern <stern@rowland.harvard.edu>2008-11-12 17:02:57 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2008-11-13 17:45:06 -0500
commit372dd6e8ed924e876f3beb598721e813ad7fa323 (patch)
tree840e634b3ff67c0a337de02947dc1b7e1b36817b /drivers/usb
parent67b2e029743a52670d77864723b4d0d40f7733b5 (diff)
USB: EHCI: fix divide-by-zero bug
This patch (as1164) fixes a bug in the EHCI scheduler. The interval value it uses is already in linear format, not logarithmically coded. The existing code can sometimes crash the system by trying to divide by zero. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Cc: David Brownell <david-b@pacbell.net> Cc: Stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/host/ehci-sched.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 4a0c5a78b2ed..a081ee65bde6 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -918,7 +918,7 @@ iso_stream_init (
918 */ 918 */
919 stream->usecs = HS_USECS_ISO (maxp); 919 stream->usecs = HS_USECS_ISO (maxp);
920 bandwidth = stream->usecs * 8; 920 bandwidth = stream->usecs * 8;
921 bandwidth /= 1 << (interval - 1); 921 bandwidth /= interval;
922 922
923 } else { 923 } else {
924 u32 addr; 924 u32 addr;
@@ -951,7 +951,7 @@ iso_stream_init (
951 } else 951 } else
952 stream->raw_mask = smask_out [hs_transfers - 1]; 952 stream->raw_mask = smask_out [hs_transfers - 1];
953 bandwidth = stream->usecs + stream->c_usecs; 953 bandwidth = stream->usecs + stream->c_usecs;
954 bandwidth /= 1 << (interval + 2); 954 bandwidth /= interval << 3;
955 955
956 /* stream->splits gets created from raw_mask later */ 956 /* stream->splits gets created from raw_mask later */
957 stream->address = cpu_to_hc32(ehci, addr); 957 stream->address = cpu_to_hc32(ehci, addr);