From 6d89252a998a695ecb0348fc2d717dc33d90cae9 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Thu, 4 Dec 2014 10:21:56 -0500 Subject: USB: EHCI: fix initialization bug in iso_stream_schedule() Commit c3ee9b76aa93 (EHCI: improved logic for isochronous scheduling) introduced the idea of using ehci->last_iso_frame as the origin (or base) for the circular calculations involved in modifying the isochronous schedule. However, the new code it added used ehci->last_iso_frame before the value was properly initialized. This patch rectifies the mistake by moving the initialization lines earlier in iso_stream_schedule(). This fixes Bugzilla #72891. Signed-off-by: Alan Stern Fixes: c3ee9b76aa93 Reported-by: Joe Bryant Tested-by: Joe Bryant Tested-by: Martin Long CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-sched.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/usb/host/ehci-sched.c') diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index e113fd73aeae..c399606f154e 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -1581,6 +1581,10 @@ iso_stream_schedule ( else next = (now + 2 + 7) & ~0x07; /* full frame cache */ + /* If needed, initialize last_iso_frame so that this URB will be seen */ + if (ehci->isoc_count == 0) + ehci->last_iso_frame = now >> 3; + /* * Use ehci->last_iso_frame as the base. There can't be any * TDs scheduled for earlier than that. @@ -1671,10 +1675,6 @@ iso_stream_schedule ( urb->start_frame = start & (mod - 1); if (!stream->highspeed) urb->start_frame >>= 3; - - /* Make sure scan_isoc() sees these */ - if (ehci->isoc_count == 0) - ehci->last_iso_frame = now >> 3; return status; fail: -- cgit v1.2.3 From c401e7b4a808d50ab53ef45cb8d0b99b238bf2c9 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Thu, 4 Dec 2014 10:22:57 -0500 Subject: USB: EHCI: adjust error return code The USB stack uses error code -ENOSPC to indicate that the periodic schedule is too full, with insufficient bandwidth to accommodate a new allocation. It uses -EFBIG to indicate that an isochronous transfer could not be linked into the schedule because it would exceed the number of isochronous packets the host controller driver can handle (generally because the new transfer would extend too far into the future). ehci-hcd uses the wrong error code at one point. This patch fixes it, along with a misleading comment and debugging message. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-sched.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/usb/host/ehci-sched.c') diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index c399606f154e..f9a332775c47 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -1604,11 +1604,11 @@ iso_stream_schedule ( */ now2 = (now - base) & (mod - 1); - /* Is the schedule already full? */ + /* Is the schedule about to wrap around? */ if (unlikely(!empty && start < period)) { - ehci_dbg(ehci, "iso sched full %p (%u-%u < %u mod %u)\n", + ehci_dbg(ehci, "request %p would overflow (%u-%u < %u mod %u)\n", urb, stream->next_uframe, base, period, mod); - status = -ENOSPC; + status = -EFBIG; goto fail; } -- cgit v1.2.3