Re: usb: musb: Scheduling of interrupt endpoints

From: Carsten Behling
Date: Tue Dec 23 2014 - 14:39:23 EST


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



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