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| author | Michael Brown | 2015-12-07 23:30:27 +0100 |
|---|---|---|
| committer | Michael Brown | 2015-12-07 23:40:47 +0100 |
| commit | ee8388ec6950ea596ddb374dcc2abb940db70aea (patch) | |
| tree | 5d479d9c4fad8f8ddd3fe18a23a30b0d24301d75 /src/drivers/usb | |
| parent | [intel] Add INTEL_NO_PHY_RST for I217-LM (diff) | |
| download | ipxe-ee8388ec6950ea596ddb374dcc2abb940db70aea.tar.gz ipxe-ee8388ec6950ea596ddb374dcc2abb940db70aea.tar.xz ipxe-ee8388ec6950ea596ddb374dcc2abb940db70aea.zip | |
[xhci] Ensure that zero-length packets are not part of a TRB chain
Some xHCI controllers (such as qemu's emulated xHCI controller) do not
correctly handle zero-length packets that are part of a TRB chain.
The zero-length TRB ends up being squashed and does not result in a
zero-length packet as seen by the device.
Work around this problem by marking the zero-length packet as
belonging to a separate transfer descriptor.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/drivers/usb')
| -rw-r--r-- | src/drivers/usb/xhci.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/drivers/usb/xhci.c b/src/drivers/usb/xhci.c index 67de0a83..48ac6a30 100644 --- a/src/drivers/usb/xhci.c +++ b/src/drivers/usb/xhci.c @@ -2606,6 +2606,12 @@ static int xhci_endpoint_stream ( struct usb_endpoint *ep, len -= trb_len; trb++; } + + /* Mark zero-length packet (if present) as a separate transfer */ + if ( zlp && ( count > 1 ) ) + trb[-2].normal.flags = 0; + + /* Generate completion for final TRB */ trb[-1].normal.flags = XHCI_TRB_IOC; /* Enqueue TRBs */ |