Re: [PATCH v2 1/1] xhci: add USB2 test mode support

[Alexander Stein <alexander.stein@systec-electronic.com>]

On Wednesday 08 February 2017 16:17:45, Mathias Nyman wrote:
> On 08.02.2017 15:44, Alexander Stein wrote:
> > This patch adds support for USB2 test mode (Test_J, Test_K,
> > Test_SE0_NAK and Test_Packet) per XHCI spec 4.19.6.
> > 
> > USB2 test mode is a required hardware feature for system integrators
> > validating their hardware according to USB spec, regarding signal
> > strength and stuff. It is purely a hardware test feature.
> > 
> > Usually you need an oscilloscope and have to enable those test modes on
> > the hardware. This will send some specific test patterns on D+/D-. There
> > is no report available (in Linux itself) as it is purely externally
> > visible. Regular USB usage is not possible at that time.
> > Anyone (well access to e.g. /dev/bus/usb/001/001 provided) can use it by
> > sending appropriate USB_PORT_FEAT_TEST requests to the hub.
> > The same feature for ehci based hosts is already available at
> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drive
> > rs/usb/host/ehci-hub.c#n1267
> > 
> > Signed-off-by: "Wang, Yu" <yu.y.wang@intel.com>
> > Signed-off-by: "Li, Guanglei" <guangleix.li@intel.com>
> > Signed-off-by: "Wu, Hao" <hao.wu@intel.com>
> > Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
> > ---
> 
> I think there's a reworked series of this feature already posted at:
> 
> http://marc.info/?l=linux-usb&m=148050258916147&w=2
> 
> But this change log is now better
> I was thinking about adding that to 4.12

Interesting, I was not aware of that. This patchset seems better and cleaner 
than my patch. It even powers off all USB3 _and_ USB2 ports. In my patch only 
USB3 ports are powered off. Also TEST_FORCE_EN seems to be supported.
Feel free to take that series and use my commit message as appropriate.

Best regards,
Alexader
-- 
Dipl.-Inf. Alexander Stein
SYS TEC electronic GmbH
alexander.stein@systec-electronic.com

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