On Fri, Feb 08, 2002, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > Ok, I've just completed a thorough set of tests regarding my previously > described packet size problem with my USB ethernet (adsl) driver. It > appears to me that either a) UHCI just can't perform like OHCI, or b) > the UHCI driver has problems. My information is reported below. I'm > running on RedHat 7.2 with their stock kernel - 2.4.7-10. > > All transfers are on a bulk-in endpoint. URBs are queued with > USB_QUEUE_BULK flag set. All URBs have their transfer_buffer_length set > to 3392 bytes (the least common multiple of ATM cell size and bulk > transfer size - 53*64). These transfers are all responses from pinging > another machine with ping data sizes of 4k and 16k. This is the simplest > way to illustrate and reproduce the problem. The problem affects > virtually all traffic, not just traffic related to pings. > > HCD URBs InWhole InCATC InURB Ping? > 1 UHCI 1 4717 3127 or 3074 3127 or 3074 No > 2 UHCI 64 4717 3127 or 3074 3010 or 3063 No > 3 OHCI 1 4717 4717 3392 and 1325 Yes > 4 OHCI 64 4717 4717 3392 and 1325 Yes > 5 OHCI 1 18868 3392*5 and variable 3392 and variable No > 6 OHCI 64 18868 18868 3392*5 and 1908 Yes > > Some notes on the table: > URBs = number of URBs queued on the pipe > InWhole = entire size of data expected to receive > InCATC = size of "bulk in" transfers as seen in CATC trace > InURB = value of "actual_length" in the URBs returned > Ping? = whether or not the ping was successful > > I would expect that from a USB driver's perspective, what he gets in > URBs should be the same regardless of what the HCD is. Is this > expectation wrong? > > I can accept the fact that for case #5 - we're simply running out of > time to receive all of the data. By the time we've queued up the URB > to get the last chunk of data, we've lost some data? Or, more likely, > we've lost some data somewhere from the first to the last chunk, but > since there is lots of data, the buffers are all full the urb until > the last one. > > Anybody have any clues here? Anything else I can provide that will help?
Which UHCI driver are you using? I assume usb-uhci since that's what RH 7.2 uses? JE _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
