From 19fa8e545f93098d403300f39bc2d4579130da74 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 30 Jan 2013 16:36:40 -0500 Subject: [PATCH] UPSTREAM: USB: EHCI: fix bug in scheduling periodic split transfers commit 3e619d04159be54b3daa0b7036b0ce9e067f4b5d upstream. This patch (as1654) fixes a very old bug in ehci-hcd, connected with scheduling of periodic split transfers. The calculations for full/low-speed bus usage are all carried out after the correction for bit-stuffing has been applied, but the values in the max_tt_usecs array assume it hasn't been. The array should allow for allocation of up to 90% of the bus capacity, which is 900 us, not 780 us. The symptom caused by this bug is that any isochronous transfer to a full-speed device with a maxpacket size larger than about 980 bytes is always rejected with a -ENOSPC error. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman (cherry picked from commit 5b70af1c0b0088151a1e7a8917527e190ddd76d7) BUG=None TEST=Together with other cherry-picks: run BVT trybots on all platforms, manually confirm that USB network/storage/input devices still work (including across suspend/resume) Change-Id: I610be3b44ef6c3006050491029520834121964be Signed-off-by: Julius Werner Reviewed-on: https://gerrit.chromium.org/gerrit/46074 Reviewed-by: Vincent Palatin --- drivers/usb/host/ehci-sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index a60679cbbf85..14d2d71163ff 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -236,7 +236,7 @@ static inline unsigned char tt_start_uframe(struct ehci_hcd *ehci, __hc32 mask) } static const unsigned char -max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 30, 0 }; +max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 125, 25 }; /* carryover low/fullspeed bandwidth that crosses uframe boundries */ static inline void carryover_tt_bandwidth(unsigned short tt_usecs[8]) -- 2.20.1