[U-Boot] [PATCH 2/2] usb: fix usb start problem with SMSC USB hub and Toshiba USB stick

[Remy Bohmer]

Hi,

2010/11/2 Anatolij Gustschin <agust at denx.de>:
> 'usb start' command often fails with Toshiba USB stick 0x930/0x6545
> connected to the SMSC USB 2.0 hub 0x424/0x2514. Debugging the
> issue showed that while bulk IN transfers with length of 13 or
> 18 the status field of the qTD token sometimes indicates trans-
> action error (XactErr) and sometimes additionally endpoint halted
> state. In the latter case resetting the USB device in error
> handling code works after clearing stall request on the endpoint.
> In the case where only XactErr bit was set the resetting doesn't
> work properly and device not ready status will be finally reported.
> This patch adds reporting endpoint stall status in case of trans-
> action errors for this hub/stick combination so that the error
> handling code can reset the device after clearing stall request
> to the endpoint.
>
> However this fix is not enough to solve 'usb start' problem
> with hub/stick combination mentioned above. Running with lot of
> debug code in ehci_submit_async() I've never seen the problem
> with usb stick recognition. After removing this debug code the
> similar problem sometimes showed up again. Therefore the patch
> also adds delay in ehci_submit_async() for above-mentioned
> hub/stick combination. Even without this delay the fix is an
> improvement since it fixes the problem with board freezy after
> subsequent failed 'usb start/stop' cycles as it was observed
> on mpc5121ads board.
>
> Signed-off-by: Anatolij Gustschin <agust at denx.de>
> ---
>  drivers/usb/host/ehci-hcd.c |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
> index c7fba10..a001143 100644
> --- a/drivers/usb/host/ehci-hcd.c
> +++ b/drivers/usb/host/ehci-hcd.c
> @@ -431,6 +431,12 @@ ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer,
>        usbsts = ehci_readl(&hcor->or_usbsts);
>        ehci_writel(&hcor->or_usbsts, (usbsts & 0x3f));
>
> +       if (dev->descriptor.idVendor == 0x930 &&
> +           dev->descriptor.idProduct == 0x6545 &&
> +           dev->parent->descriptor.idVendor == 0x424 &&
> +           dev->parent->descriptor.idProduct == 0x2514)
> +               wait_ms(10);
> +

I have to say that I have a problem with this construction.
This will solve only 1 particular situation where the user has exactly
this USB stick and exactly this hub.
If he uses another hub, he can have the same problem. If he use
another USB-stick he also can run into this problem.
What is the real cause of this issue, and can it be solved in a
generic way? I feel the problem is still not understood.

So, I NAK this patch.. Sorry...

Remy