Hi,
In include/linux/usb.h, there is
/*
* timeouts, in milliseconds, used for sending/receiving control messages
* they typically complete within a few frames (msec) after they're issued
* USB identifies 5 second timeouts, maybe more in a few cases, and a few
* slow devices (like some MGE Ellipse UPSes) actually push that limit.
*/
#define USB_CTRL_GET_TIMEOUT 5000
#define USB_CTRL_SET_TIMEOUT 5000
However several callers of usb_stor_control_msg() have timeout argument
specified as n*HZ, for example in drivers/usb/storage/transport.c:
result = usb_stor_control_msg(us, us->send_ctrl_pipe,
USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
USB_ENDPOINT_HALT, endp,
NULL, 0, 3*HZ);
result = usb_stor_control_msg(us, us->recv_ctrl_pipe,
US_BULK_GET_MAX_LUN,
USB_DIR_IN | USB_TYPE_CLASS |
USB_RECIP_INTERFACE,
0, us->ifnum, us->iobuf, 1, 10*HZ);
result = usb_stor_control_msg(us, us->send_ctrl_pipe,
request, requesttype, value, index, data, size,
5*HZ);
I'm just wondering whether those callers should have timeouts in ms (so
3*HZ -> 3000), or whether the definitions of USB_CTRL_GET/SET_TIMEOUT
should be 5*HZ? Or is HZ always 1000 these days?
Mark
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