Hi, Doug Anderson <dianders@xxxxxxxxxxxx> writes: >> Douglas Anderson <dianders@xxxxxxxxxxxx> writes: >>> Until we have logic to determine which devices share the same TT let's >>> add logic to assume that all devices on a given dwc2 controller are on >>> one single_tt hub. This is better than the previous code that assumed >>> that all devices were on one multi_tt hub, since single_tt hubs >>> appear (in my experience) to be much more common and any schedule that >>> would work on a single_tt hub will also work on a multi_tt hub. This >>> will prevent more than 8 total low/full speed devices to be on the bus >>> at one time, but that's a reasonable restriction until we've made things >>> smarter. >>> >>> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> >>> --- >>> Changes in v3: >>> - Assuming single_tt is new for v3; not terribly well tested (yet). >>> >>> Changes in v2: None >>> >>> drivers/usb/dwc2/core.h | 1 + >>> drivers/usb/dwc2/hcd_queue.c | 40 +++++++++++++++++++++++++++++++++++++++- >>> 2 files changed, 40 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h >>> index 567ee2c9e69f..09aa2b5ae29e 100644 >>> --- a/drivers/usb/dwc2/core.h >>> +++ b/drivers/usb/dwc2/core.h >>> @@ -782,6 +782,7 @@ struct dwc2_hsotg { >>> u16 periodic_usecs; >>> unsigned long periodic_bitmap[DIV_ROUND_UP(TOTAL_PERIODIC_USEC, >>> BITS_PER_LONG)]; >>> + bool has_split[8]; >> >> why don't you use a u8 instead then just set each bit for each >> "has_split" you need to take care of. This array is kinda ugly. > > Let's actually drop this patch completely. Julius and I sat down and > he talked me through things, and with my current understanding the > current microframe scheduler in dwc2 is broken enough that small > little band-aids like this will do little more than just push the > problems around. > > I'm a good portion of the way through a better microframe scheduler. > I have no doubt that it won't be perfect, but hopefully it will at > least be based in reality... > > My latest thinking on the patches in this series: > > 1. usb: dwc2: rockchip: Make the max_transfer_size automatic > > I'll probably separate this out into its own patch so I can stop > sending it as part of this series. ...or if someone wanted to land it > then I won't bother. > > > 2. usb: dwc2: host: Get aligned DMA in a more supported way > > Still can land any time and has good benefits. I believe that I can't > separate this because it will cause conflicts with scheduler patches. > > > 3. usb: dwc2: host: Add scheduler tracing > > Would be nice to land. > > > 4. usb: dwc2: host: Rewrite the microframe scheduler > 5. usb: dwc2: host: Keep track of and use our scheduled microframe > 6. usb: dwc2: host: Assume all devices are on one single_tt hub > > Please drop patches 4-6 right now. > > > 7. usb: dwc2: host: Add a delay before releasing periodic bandwidth > 8. usb: dwc2: host: Giveback URB in tasklet context if you can, it's best to send a new series with the changes. This makes mine and John's life a lot easier :-) > I'll probably move these back up in the series (like in v2) and put > microframe rewrite atop them. With my current understanding the > scheduling is so broken today that the concerns Alan brought up can > wait until we have a proper scheduler to be addressed. In the > meantime getting the huge boost in interrupt speed will help with > dwc2's correctness (and performance) because it means we're much less > likely to miss SOF interrupts. > > If anyone has any review time, giving a review to v2 of these patches > would be helpful. Otherwise I'll double check that v2 still looks > good with my current understanding and eventually post them again. That would have to be someone experienced with that IP. I don't even have docs :-) -- balbi
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