Hi, On Wed, Mar 30, 2016 at 09:14:18AM +0300, Felipe Balbi wrote: > > Hi again, > > Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> writes: > > Bin Liu <b-liu@xxxxxx> writes: > >> On Fri, Mar 18, 2016 at 08:59:48AM +0200, Felipe Balbi wrote: > >>> > >>> Hi, > >>> > >>> Bin Liu <binmlist@xxxxxxxxx> writes: > >>> > [ text/plain ] > >>> > Hi, > >>> > > >>> > On Fri, Mar 11, 2016 at 6:54 AM, Felipe Balbi > >>> > <felipe.balbi@xxxxxxxxxxxxxxx> wrote: > >>> >> previously we were using a maximum of 32 TRBs per > >>> >> endpoint. With each TRB being 16 bytes long, we were > >>> >> using 512 bytes of memory for each endpoint. > >>> >> > >>> >> However, SLAB/SLUB will always allocate PAGE_SIZE > >>> >> chunks. In order to better utilize the memory we > >>> >> allocate and to allow deeper queues for gadgets > >>> >> which would benefit from it (g_ether comes to mind), > >>> >> let's increase the maximum to 256 TRBs which rounds > >>> >> up to 4096 bytes for each endpoint. > >>> > > >>> > Do we want to increase the same for event ring buffers as > >>> > while, which is allocated by dma_alloc_coherent(), which > >>> > is also at PAGE_SIZE chunks, right? > >>> > >>> I could, but that's much less important. Currently we have up to 2 > >> > >> I agree it is less important, the only issue I see is wasting of memory. > >> The device I am working on right now has two dwc3 controllers, each > >> allocates 16 event buffers, so for the total of 128KB allocated pages, > >> only 8KB is really used, 120KB is wasted. > >> > >> Seems dma pool makes more sense in here? > > > > I don't know. I think the real thing is that I really need to revisit > > that part of the code/databook. The whole "multiple interrupters" seems > > like it's only really necessary for host side. Which means that we could > > drop all the loops for multiple event buffers and always use a single > > one. > > > > Do you wanna test the following ? > > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > > index 17fd81447c9f..ebb3ee9c06f1 100644 > > --- a/drivers/usb/dwc3/core.c > > +++ b/drivers/usb/dwc3/core.c > > @@ -237,8 +237,7 @@ static int dwc3_alloc_event_buffers(struct dwc3 *dwc, unsigned length) > > int num; > > int i; > > > > - num = DWC3_NUM_INT(dwc->hwparams.hwparams1); > > - dwc->num_event_buffers = num; > > + dwc->num_event_buffers = 1; > > > > dwc->ev_buffs = devm_kzalloc(dwc->dev, sizeof(*dwc->ev_buffs) * num, > > GFP_KERNEL); > > > > I'll re-read what these bits actually mean. I have a strong feeling we > > could (should?) be ignoring them for the peripheral side. > > Okay, so when we're configuring the endpoints, we could route endpoint > interrupts to different event buffers. I really think that's really > unimportant for us, specially since we end up using a single IRQ line. > > I guess I'll just go ahead and remove that code. If it turns out we > decide to use it, we shouldn't really be using a loop in the hardirq > handler anyway. Sounds good to me, I only see one evt buffer is used in all my devices, even thought multi buffers are allocated based on hwparams1. Regards, -Bin. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
