There were some reports[1] of isp1760 USB driver malfunctioning with high speed devices, noticed on Blackfin and PowerPC targets. These reports indicated that the original Philips 'pehcd'[2] driver worked fine. We've noticed the same issue with an ARM RealView platform. This happens under load (with only some mass storage devices, not all, just as in another report[3]): error bit is set in DW3 error bit is set in DW3 error bit is set in DW3 usb 1-1.2: device descriptor read/64, error -32 It appears that the 'pehcd' driver checks the X bit only if the transaction is halted (H bit), otherwise the error is so far insignificant. The ISP176x chips were modeled after EHCI, and EHCI spec says (thanks to Alan Stern for pointing out): "Transaction errors cause the status field to be updated to reflect the type of error, but the transaction continues to be retried until the Active bit is set to 0. When the error counter reaches 0, the Halt bit is set and the Active bit is cleared." So, just as the original Philips driver, isp1760 must report the error only if the transaction error and the halt bits are set. [1] http://markmail.org/message/lx4qrlbrs2uhcnly [2] svn co svn://sources.blackfin.uclinux.org/linux-kernel/trunk/drivers/usb/host -r 5494 See pehci.c:pehci_hcd_update_error_status(). [3] http://blackfin.uclinux.org/gf/tracker/5148 Signed-off-by: Anton Vorontsov <avorontsov@xxxxxxxxxx> --- On Thu, May 06, 2010 at 03:53:54PM -0400, Alan Stern wrote: [...] > > I didn't find where exactly ISP1760 spec mandates 'H && X' > > handling (maybe it's in the EHCI spec?), > > Yes, it is described implicitly in the EHCI spec, section 4.10.3. Thanks! I've added this to the commit message. On Thu, May 06, 2010 at 03:23:28PM -0400, Mike Frysinger wrote: > On Thu, May 6, 2010 at 15:15, Anton Vorontsov wrote: > > [3] http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=5148 > > i doubt you feel like resending, but this is a better link: > http://blackfin.uclinux.org/gf/tracker/5148 Yeah. I've changed the link, thanks. drivers/usb/host/isp1760-hcd.c | 7 +++---- 1 files changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/usb/host/isp1760-hcd.c b/drivers/usb/host/isp1760-hcd.c index 9f01293..9989c0b 100644 --- a/drivers/usb/host/isp1760-hcd.c +++ b/drivers/usb/host/isp1760-hcd.c @@ -713,12 +713,11 @@ static int check_error(struct ptd *ptd) u32 dw3; dw3 = le32_to_cpu(ptd->dw3); - if (dw3 & DW3_HALT_BIT) + if (dw3 & DW3_HALT_BIT) { error = -EPIPE; - if (dw3 & DW3_ERROR_BIT) { - printk(KERN_ERR "error bit is set in DW3\n"); - error = -EPIPE; + if (dw3 & DW3_ERROR_BIT) + pr_err("error bit is set in DW3\n"); } if (dw3 & DW3_QTD_ACTIVE) { -- 1.7.0.5 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
