This fixes a rare protocol bug that's been with us since at least 2.4 days; please merge.
- Dave
This fixes a longstanding bug in the OHCI driver, inherited from the 2.4 code. It also fixes a related comment in the EHCI driver, which came when the EHCI code was first derived from OHCI. (The EHCI code doesn't have that bug; the comment was effectively "FIXME add bug".) The bug: control-IN transfers with no data stages have status stages with an IN packet (like a control-OUT transfer), instead of using an OUT packet. See figure 8-37 of the USB spec. The current code makes trouble with some peripheral hardware and zero length IN transfers (scarce in the Real World). Signed-off-by: David Brownell <[EMAIL PROTECTED]> --- 1.77/drivers/usb/host/ehci-q.c 2005-02-16 15:53:38 -08:00 +++ edited/drivers/usb/host/ehci-q.c 2005-03-02 08:59:20 -08:00 @@ -522,7 +522,7 @@ else buf = 0; - // FIXME this 'buf' check break some zlps... + /* for zero length DATA stages, STATUS is always IN */ if (!buf || is_input) token |= (1 /* "in" */ << 8); /* else it's already initted to "out" pid (0 << 8) */ --- 1.74/drivers/usb/host/ohci-q.c 2005-01-10 12:51:55 -08:00 +++ edited/drivers/usb/host/ohci-q.c 2005-03-01 13:28:30 -08:00 @@ -662,7 +662,7 @@ /* NOTE: mishandles transfers >8K, some >4K */ td_fill (ohci, info, data, data_len, urb, cnt++); } - info = is_out + info = (is_out || data_len == 0) ? TD_CC | TD_DP_IN | TD_T_DATA1 : TD_CC | TD_DP_OUT | TD_T_DATA1; td_fill (ohci, info, data, 0, urb, cnt++);
