Re: [PATCH] usb: musb: return -ESHUTDOWN in urb when three-strikes error happened

[Bin Liu <b-liu@ti.com>]

On Thu, May 14, 2020 at 02:55:49PM -0400, Alan Stern wrote:
> On Thu, May 14, 2020 at 12:00:23PM -0500, Bin Liu wrote:
> 
> > > Still, it's worth pointing out that this change abuses the API (perhaps 
> > > mentioning it in a comment).  And it still would be preferable to fix 
> > 
> > Okay, I will add those notes in comment in v2.
> > 
> > > the drivers in question, impractical though that may be.  (I have a hard 
> > > time believing there are really 500 of them getting this wrong...)
> > 
> > I am not sure about it either, but yeah it is not practical to fix the
> > issue in device drivers. So far I have seen 3 reports of this issue:
> > 
> > 1. with FTDI usb-serial adapter, the issue is in the usb serial generic
> > driver;
> 
> It shouldn't be hard to fix this.  We don't even need a delayed retry; 
> the driver can simply treat -EPROTO as an unrecoverable error, just like 
> -ESHUTDOWN.

This is just an example showing that it is not practical to fix the
problem in device drivers.

BTY, I just briefly searched the drivers/ folder, there are only three
drivers handle -EPROTO specifically in rx callback and bail out. So
seems most drivers do not care about -EPROTO.

-Bin.