From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tilman Schmidt Date: Sat, 19 May 2012 00:38:41 +0200 Subject: [ath9k-devel] [RFC 13/13] USB: Disable hub-initiated LPM for comms devices. In-Reply-To: <20120517173150.GE4967@xanatos> References: <3c634afbbe15598cdcbf77bb9393d22ad4bfa373.1337203535.git.sarah.a.sharp@linux.intel.com> <4FB53054.9070309@imap.cc> <20120517173150.GE4967@xanatos> Message-ID: <4FB6CF71.7080307@imap.cc> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ath9k-devel@lists.ath9k.org Am 17.05.2012 19:31, schrieb Sarah Sharp: > On Thu, May 17, 2012 at 07:07:32PM +0200, Tilman Schmidt wrote: >> >> I follow the argument for class drivers. But this patch also >> modifies drivers for specific existing USB 2.0 only devices >> which are unlikely to ever grow USB 3.0 support, such as the >> Gigaset ISDN driver: >> >>> drivers/isdn/gigaset/bas-gigaset.c | 1 + >>> drivers/isdn/gigaset/usb-gigaset.c | 1 + > > Is there a particular reason why you think that driver is unlikely to > ever get USB 3.0 support? Actually, there is. :-) - The USB devices driven by this driver aren't built anymore. - Their USB interface design is quite, um, idiosyncratic, and it's pretty unlikely that anyone will reuse it. (At least I truly hope no one will.) - Their successor models have completely different and incompatible USB interfaces which this driver is unable to handle. >> What is the interest of setting the disable_hub_initiated_lpm >> flag for these? > > It's partially to lay the foundation for anyone who wants to make a USB > 3.0 communications driver in the future. They're likely to start from > some USB 2.0 class driver, and copy a lot of code. If they notice that > flag is set in all the USB communications class drivers, they're likely > to set it as well. You've got a point there. > I'm not quite sure where the best place to provide documentation on the > flag is. I've added the kernel doc comments to the structure, but maybe > it needs to be documented somewhere in Documentation/usb/? Documentation/usb/power-management.txt would seem like a natural place. Although it appears to limit itself to "suspending" in its first paragraph, it does have a section "xHCI hardware link PM" at the end already, added by Andiry Xu on 2011-09-23. Hmmm, that section seems to suggest that LPM exists for USB2, too. Perhaps I should reconsider my attitude towards your patch. Thanks, Tilman -- Tilman Schmidt E-Mail: tilman at imap.cc Bonn, Germany Diese Nachricht besteht zu 100% aus wiederverwerteten Bits. Unge?ffnet mindestens haltbar bis: (siehe R?ckseite) -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 262 bytes Desc: OpenPGP digital signature Url : http://lists.ath9k.org/pipermail/ath9k-devel/attachments/20120519/39e38f4d/attachment.pgp