* Re: usb: musb: Scheduling of interrupt endpoints [not found] <54947E99.4010908@ridgerun.com> @ 2014-12-23 14:59 ` Carsten Behling 2014-12-23 18:27 ` Felipe Balbi 2014-12-23 19:39 ` Carsten Behling 0 siblings, 2 replies; 6+ messages in thread From: Carsten Behling @ 2014-12-23 14:59 UTC (permalink / raw) To: linux-usb; +Cc: balbi, linux-kernel Would it help if I send a patch as a suggestion and as basis for discussion? On 12/19/2014 01:38 PM, Carsten Behling wrote: > Hi all, > > Long time ago, TI shipped a kernel named > linux-2.6.32.17-psp03.01.01.39 with an additional kernel option > for scheduling of interrupt endpoints. > > AFAIK, this seems to be the only possibility to attach more that 4 in > endpoints to MUSB (at least on a DM368). > > This feature reserves one hardware endpoint unit to time schedule > interrupt in endpoints based > on its bInterval value triggered by the SOF interrupt. > > I didn't find any discussion about adding such a feature to the > mainline kernel. > IMHO, this feature is absolutely necessary. But there may be reasons, > not to add it (e.g. CPU load). > > Please let me know your thoughts and ideas. > > Best regards > -Carsten > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: usb: musb: Scheduling of interrupt endpoints 2014-12-23 14:59 ` usb: musb: Scheduling of interrupt endpoints Carsten Behling @ 2014-12-23 18:27 ` Felipe Balbi 2014-12-23 20:16 ` Carsten Behling 2014-12-23 19:39 ` Carsten Behling 1 sibling, 1 reply; 6+ messages in thread From: Felipe Balbi @ 2014-12-23 18:27 UTC (permalink / raw) To: Carsten Behling; +Cc: linux-usb, balbi, linux-kernel [-- Attachment #1: Type: text/plain, Size: 224 bytes --] Hi, On Tue, Dec 23, 2014 at 08:59:39AM -0600, Carsten Behling wrote: > Would it help if I send a patch as a suggestion and as basis for > discussion? yes, it would also help if you didn't top-post :-) -- balbi [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: usb: musb: Scheduling of interrupt endpoints 2014-12-23 18:27 ` Felipe Balbi @ 2014-12-23 20:16 ` Carsten Behling 2014-12-23 23:48 ` Felipe Balbi 0 siblings, 1 reply; 6+ messages in thread From: Carsten Behling @ 2014-12-23 20:16 UTC (permalink / raw) To: balbi; +Cc: linux-usb, linux-kernel Hi Felipe, On 12/23/2014 12:27 PM, Felipe Balbi wrote: > Hi, > > On Tue, Dec 23, 2014 at 08:59:39AM -0600, Carsten Behling wrote: >> Would it help if I send a patch as a suggestion and as basis for >> discussion? > yes, it would also help if you didn't top-post :-) > So would you suggestion be to port that feature from the old linux-2.6.32.17-psp03.01.01.39 kernel from TI or should we rather add a tree based implementation as done for OHCI? -Carsten ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: usb: musb: Scheduling of interrupt endpoints 2014-12-23 20:16 ` Carsten Behling @ 2014-12-23 23:48 ` Felipe Balbi 0 siblings, 0 replies; 6+ messages in thread From: Felipe Balbi @ 2014-12-23 23:48 UTC (permalink / raw) To: Carsten Behling; +Cc: balbi, linux-usb, linux-kernel [-- Attachment #1: Type: text/plain, Size: 1444 bytes --] Hi, On Tue, Dec 23, 2014 at 02:16:57PM -0600, Carsten Behling wrote: > >On Tue, Dec 23, 2014 at 08:59:39AM -0600, Carsten Behling wrote: > >>Would it help if I send a patch as a suggestion and as basis for > >>discussion? > >yes, it would also help if you didn't top-post :-) > > > So would you suggestion be to port that feature from the old > linux-2.6.32.17-psp03.01.01.39 > kernel from TI or should we rather add a tree based implementation as done > for OHCI? quite frankly, I don't know and, because of my email domain, I can't really say out loud what I really think about those old TI releases :-) IMHO, the best thing would be to completely ignore old kernels and have a critical look at that part of the code on MUSB Host. Right now, MUSB has a really brain dead endpoint allocation algorithm and it only works for bulk (dynamic allocation, that is). Interrupt and isochronous are left out of dynamic allocation which, IMHO, makes no sense what so ever. I guess the users of MUSB would benefit a whole lot more if someone were to redesign that logic altogether so that all endpoints can be dynamically allocated. One easy way to test things out is to attach a ton of hubs and several USB Serial adapters to a single MUSB port. All hubs and all USB serial adapters - of course, as long as you follow USB spec's limitation on maximum tier level and maximum number of devices. cheers -- balbi [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: usb: musb: Scheduling of interrupt endpoints 2014-12-23 14:59 ` usb: musb: Scheduling of interrupt endpoints Carsten Behling 2014-12-23 18:27 ` Felipe Balbi @ 2014-12-23 19:39 ` Carsten Behling 2014-12-23 23:50 ` Felipe Balbi 1 sibling, 1 reply; 6+ messages in thread From: Carsten Behling @ 2014-12-23 19:39 UTC (permalink / raw) To: linux-usb; +Cc: balbi, linux-kernel The following comment can be found in 'musb_schedule()': '* REVISIT what we really want here is a regular schedule tree * like e.g. OHCI uses.' So I assume the best practice would be to make an implementation based on the code in in ohci-q.c. And it would be waste of time to port the old interrupt endpoint scheduling feature of TI. Am I right? On 12/23/2014 08:59 AM, Carsten Behling wrote: > Would it help if I send a patch as a suggestion and as basis for > discussion? > > On 12/19/2014 01:38 PM, Carsten Behling wrote: >> Hi all, >> >> Long time ago, TI shipped a kernel named >> linux-2.6.32.17-psp03.01.01.39 with an additional kernel option >> for scheduling of interrupt endpoints. >> >> AFAIK, this seems to be the only possibility to attach more that 4 in >> endpoints to MUSB (at least on a DM368). >> >> This feature reserves one hardware endpoint unit to time schedule >> interrupt in endpoints based >> on its bInterval value triggered by the SOF interrupt. >> >> I didn't find any discussion about adding such a feature to the >> mainline kernel. >> IMHO, this feature is absolutely necessary. But there may be reasons, >> not to add it (e.g. CPU load). >> >> Please let me know your thoughts and ideas. >> >> Best regards >> -Carsten >> > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: usb: musb: Scheduling of interrupt endpoints 2014-12-23 19:39 ` Carsten Behling @ 2014-12-23 23:50 ` Felipe Balbi 0 siblings, 0 replies; 6+ messages in thread From: Felipe Balbi @ 2014-12-23 23:50 UTC (permalink / raw) To: Carsten Behling; +Cc: linux-usb, balbi, linux-kernel [-- Attachment #1: Type: text/plain, Size: 627 bytes --] Hi, A: No. Q: Should I include quotations after my reply? On Tue, Dec 23, 2014 at 01:39:14PM -0600, Carsten Behling wrote: > The following comment can be found in 'musb_schedule()': > > '* REVISIT what we really want here is a regular schedule tree > * like e.g. OHCI uses.' > > So I assume the best practice would be to make an implementation based > on the code in in ohci-q.c. And it would be waste of time to port the > old interrupt endpoint scheduling feature of TI. > > Am I right? Frankly, OHCI is a better example than TI's MUSB from 200 years ago, that's correct :-) cheers -- balbi [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 6+ messages in thread
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2014-12-23 14:59 ` usb: musb: Scheduling of interrupt endpoints Carsten Behling
2014-12-23 18:27 ` Felipe Balbi
2014-12-23 20:16 ` Carsten Behling
2014-12-23 23:48 ` Felipe Balbi
2014-12-23 19:39 ` Carsten Behling
2014-12-23 23:50 ` Felipe Balbi
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