From 372dd6e8ed924e876f3beb598721e813ad7fa323 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 12 Nov 2008 17:02:57 -0500 Subject: [PATCH] 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 Cc: David Brownell Cc: Stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-sched.c | 4 ++-- 1 file 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 ( */ stream->usecs = HS_USECS_ISO (maxp); bandwidth = stream->usecs * 8; - bandwidth /= 1 << (interval - 1); + bandwidth /= interval; } else { u32 addr; @@ -951,7 +951,7 @@ iso_stream_init ( } else stream->raw_mask = smask_out [hs_transfers - 1]; bandwidth = stream->usecs + stream->c_usecs; - bandwidth /= 1 << (interval + 2); + bandwidth /= interval << 3; /* stream->splits gets created from raw_mask later */ stream->address = cpu_to_hc32(ehci, addr); -- 2.30.2