Re: [PATCH 0/1] Fixes to the USB 3.0 detection as 2.0 on AMD platform
From: Gavin Guo
Date: Fri Jul 11 2014 - 19:32:42 EST
On Fri, Jul 11, 2014 at 2:22 PM, Gavin Guo <gavin.guo@xxxxxxxxxxxxx> wrote:
> Hi Sarah and Mathias,
> As the discussion in http://comments.gmane.org/gmane.linux.usb.general/107011,
> I found that [AMD] FCH USB XHCI Controller [1022:7814] the USB 3.0 disk
> can't work in SuperSpeed after several times of hotplug. After doing some
> experiments and bisection, I found the bug is caused by
> 41e7e056cdc662f704fa9262e5c6e213b4ab45dd (USB: Allow USB 3.0 ports to be
> disabled.). And the bug can be fixed by not executing the
> hub_usb3_port_disable() function. I also found that the port status is
> already in RxDetect before setting the port to Disabled in
> hub_usb3_port_disable() function. So, there are 2 ways to fix the bug:
> 1) Check if the Vendor/Device id is [1022:7814] at the beginning of
> hub_usb3_port_disable() function. If yes, return without executing the
> remaining code.
> 2) Check if the port status is already in RxDetect, if yes, return without
> executing the remaining code.
> The second method seems more reasonable, so the patch is the implementation
> of the second one. But it will affect more platforms and I don't know if
> there'll be any negative result. Otherwise, if the first one is correct,
> I can reimplement a new one.
> I'm appreciated if you can give me some advice, or if there is any thing I missed.
> Gavin Guo (1):
> usb: Check if port status is equal to RxDetect
> drivers/usb/core/hub.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
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