Message-ID: <565DB7FF.2040903@linux.intel.com>
Date: Tue, 01 Dec 2015 17:08:47 +0200
From: Mathias Nyman <mathias.nyman@linux.intel.com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0
MIME-Version: 1.0
To: Felipe Balbi <balbi@ti.com>, daniel@quora.org
CC: linux-usb@vger.kernel.org, stern@rowland.harvard.edu,
        linux-kernel@vger.kernel.org
Subject: Re: [TESTPATCH v2] xhci: fix usb2 resume timing and races.
References: <CAMVG2sus03xnbCSikFGG+t2fXM_gME_jMeGpGHxVuVRks07WCg@mail.gmail.com> <1448958418-6114-1-git-send-email-mathias.nyman@linux.intel.com> <87d1uq1bpz.fsf@saruman.tx.rr.com>
In-Reply-To: <87d1uq1bpz.fsf@saruman.tx.rr.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1311
Lines: 36

On 01.12.2015 16:32, Felipe Balbi wrote:
>
> Hi,
>
> Mathias Nyman <mathias.nyman@linux.intel.com> writes:
>> usb2 ports need to signal resume for 20ms before moving to U0 state.
>
> at least 20ms ;-) Recently, we decided to drive resume for 40ms to
> support devices with broken FW.
>

True, but specs talk about 20ms, and I'm just trying to give some context for what's
going on. This testpatch doesn't touch the timings.

Daniel is able to trigger a USB2 xhci resume issue which I hope is fixed with this patch.
This is especially made for his setup running a 4.3 kernel

If this works I'll clean up all the "20ms" in the commit message and comments.

Just noticed that xhci USB2 host initiated resume uses a hardcoded msleep(20).
That needs to be changed to USB_RESUME_TIMEOUT at some point.
For now I'm just interested in knowing if this patch works.

>
> this 'v2' note doesn't have to go into commit log, IMO.
>

It's going to be cleaned out as well, just there to explain to Daniel, and the world why
a second version of the testpatch was created.

-Mathias
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/