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authorSarah Sharp <sarah.a.sharp@linux.intel.com>2011-06-17 00:06:04 +0400
committerSarah Sharp <sarah.a.sharp@linux.intel.com>2011-06-17 22:28:21 +0400
commita9e758634f464ffb09344821a9f0b5a5c6df2b3e (patch)
tree5fe6502609769a90e77a7b9b91e2e2e691235572 /Documentation/usb
parentb3df3f9c7df9a8d85e03e158d35487618a160901 (diff)
downloadlinux-a9e758634f464ffb09344821a9f0b5a5c6df2b3e.tar.xz
USB: Fix up URB error codes to reflect implementation.
Documentation/usb/error-codes.txt mentions that urb->status can be set to -EXDEV, if the isochronous transfer was not fully completed. However, in practice, EHCI, UHCI, and OHCI all only set -EXDEV in the individual frame status, never in the URB status. Those host controller actually always pass in a zero status to usb_hcd_giveback_urb, and rely on the core to set the appropriate status value. The xHCI driver ran into issues with the uvcvideo driver when it tried to set -EXDEV in urb->status, because the driver refused to submit URBs, and the userspace camera application's video froze. Clean up the documentation to reflect the actual implementation. Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu>
Diffstat (limited to 'Documentation/usb')
-rw-r--r--Documentation/usb/error-codes.txt9
1 files changed, 8 insertions, 1 deletions
diff --git a/Documentation/usb/error-codes.txt b/Documentation/usb/error-codes.txt
index d83703ea74b2..b3f606b81a03 100644
--- a/Documentation/usb/error-codes.txt
+++ b/Documentation/usb/error-codes.txt
@@ -76,6 +76,13 @@ A transfer's actual_length may be positive even when an error has been
reported. That's because transfers often involve several packets, so that
one or more packets could finish before an error stops further endpoint I/O.
+For isochronous URBs, the urb status value is non-zero only if the URB is
+unlinked, the device is removed, the host controller is disabled, or the total
+transferred length is less than the requested length and the URB_SHORT_NOT_OK
+flag is set. Completion handlers for isochronous URBs should only see
+urb->status set to zero, -ENOENT, -ECONNRESET, -ESHUTDOWN, or -EREMOTEIO.
+Individual frame descriptor status fields may report more status codes.
+
0 Transfer completed successfully
@@ -132,7 +139,7 @@ one or more packets could finish before an error stops further endpoint I/O.
device removal events immediately.
-EXDEV ISO transfer only partially completed
- look at individual frame status for details
+ (only set in iso_frame_desc[n].status, not urb->status)
-EINVAL ISO madness, if this happens: Log off and go home