Re: kern/54070: urtwn(4) does not work on OHCI

[Nick Hudson <nick.hudson%gmx.co.uk@localhost>]

The following reply was made to PR kern/54070; it has been noted by GNATS.

From: Nick Hudson <nick.hudson%gmx.co.uk@localhost>
To: Andreas Gustafsson <gson%gson.org@localhost>
Cc: gnats-bugs%netbsd.org@localhost
Subject: Re: kern/54070: urtwn(4) does not work on OHCI
Date: Wed, 27 Nov 2019 20:11:51 +0000

 On 27/11/2019 07:48, Andreas Gustafsson wrote:
 > Nick Hudson wrote:
 >> What is the error code OHCI_CC_DATA_UNDERRUN?
 >
 > Yes.
 >
 >> Maybe OHCI_TD_R should be used more?
 >
 > I think then we would run into the issue discussed in the following
 > quote from http://www.fysnet.net/docs/vol8_future.pdf:
 >
 > "If this bit is set, the controller will mark the TD as a successful
 > transfer, however, the controller will continue on to the next TD
 > pointed to by the NextTD field. Continuing to the next TD may not be
 > what you planned on."
 
 Ok, I see that you're trying to implement the recommendation in the PDF.
 
 I think it's best to remove OHCI_TD_R completely for bulk/interrupt
 transfers.
 
   http://src.illumos.org/source/xref/netbsd-src/sys/dev/usb/ohci.c#666
 
 I haven't thought about control transfers though.
 
 Nick