[U-Boot] [PATCH 5/7] usb: hub: Increase device enumeration timeout for broken drives

From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 5/7] usb: hub: Increase device enumeration timeout for broken drives
Date: Sun, 14 Apr 2013 19:17:34 +0200	[thread overview]
Message-ID: <201304141917.34483.marex@denx.de> (raw)
In-Reply-To: <CAFp+6iFfkqBiJ18S837LfYViOpqEvPj+KHf8hNoEV=tKNFUSXg@mail.gmail.com>

Dear Vivek Gautam,

> Hi Marek,
> 
> On Thu, Apr 4, 2013 at 9:28 AM, Marek Vasut <marex@denx.de> wrote:
> > Dear Vivek Gautam,
> > 
> >> Hi Marek,
> >> 
> >> On Thu, Mar 28, 2013 at 8:02 PM, Marek Vasut <marex@denx.de> wrote:
> >> > Dear Vivek Gautam,
> >> > 
> >> >> Few broken usb mass storage devices can take some time to set
> >> >> Current Connect Status (CCS) and Connect Status Change (CSC) in
> >> >> Port status register after an attach.
> >> >> So increasing some timeout when both CCS and CSC bits are not set.
> >> >> 
> >> >> Signed-off-by: Amar <amarendra.xt@samsung.com>
> >> >> Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
> >> > 
> >> > Can we not postpone checking of these CCS and CSC bits for such broken
> >> > devices? This'd at least allow the "good" devices to be detected
> >> > quickly and while these are handled, this would give some time for
> >> > the "bad" ones to do their job too.
> >> 
> >> We are thinking of one approach here.
> >> Iterating over all the ports once, so that we find 'good' ports and
> >> 'bad' ports By 'bad' port we mean that either the device connected to
> >> it is bad or nothing is connected
> >> to this port.
> >> Once we are done with "usb_hub_port_connect_change()" and other jobs
> >> for 'good' ports,
> >> we iterate once again on bad ports.
> >> Not sure how good this approach :-(.  Any suggestions ?
> > 
> > That might just work, but I wonder if it's worth it. It's a pity we can't
> > make a list of those as they're not even probed yet :(
> 
> True, but at this point of time atleast the CSC and CCS bits tell us
> about whether something is connected or not. Right ?
> So lets make the ports on which nothing is connected 'bad' and probe
> them later so that if something is connected to these,
> job can be done.
> 
> If you are fine i may drop this patch from this series for now and
> come back with a solution.
> By the time i can update the patch-series.

Sorry for the late reply again. I think the best way around here would be to 
make the delay configurable, possibly as an argument to "usb reset" with some 
reasonable default value, what do you think?

Best regards,
Marek Vasut