| Message ID | 201301221813.57741.arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
On 22.01.2013 19:13, Arnd Bergmann wrote: > On Monday 21 January 2013, Greg KH wrote: >>> >>> I don't know a lot about USB, but I always assumed that this was not >>> a normal condition and that there are only a couple of URBs per endpoint >>> used at a time. Maybe Greg or someone else with a USB background can >>> shed some light on this. >> >> There's no restriction on how many URBs a driver can have outstanding at >> once, and if you have a system with a lot of USB devices running at the >> same time, there could be lots of URBs in flight depending on the number >> of host controllers and devices and drivers being used. I only use one host controller and (in this test) two usb devices with the same driver. > Ok, thanks for clarifying that. I read some more of the em28xx driver, > and while it does have a bunch of URBs in flight, there are only five > audio and five video URBs that I see simultaneously being submitted, > and then resubmitted from their completion handlers. I think this > means that there should be 10 URBs active at any given time in this > driver, which does not explain why we get 256 allocations. I think the audio part of the em28xx bridge is not used in my DVB tests. Are there other allocations from orion-ehci directly? Maybe something special for isochronous transfers (since there is no problem with my other dvb sticks using bulk transfers)? > I also noticed that the initial submissions are all atomic but don't > need to, so it may be worth trying the patch below, which should also > help in low-memory situations. We could also try moving the resubmission > into a workqueue in order to let those be GFP_KERNEL, but I don't think > that will help. I built a linux-3.7.4 with the em28xx patch and both of your dma-mapping.c patches. I still see the ERROR: 1024 KiB atomic DMA coherent pool is too small! Soeren
diff --git a/drivers/media/usb/em28xx/em28xx-audio.c b/drivers/media/usb/em28xx/em28xx-audio.c index 2fdb66e..8b789f4 100644 --- a/drivers/media/usb/em28xx/em28xx-audio.c +++ b/drivers/media/usb/em28xx/em28xx-audio.c @@ -177,12 +177,12 @@ static int em28xx_init_audio_isoc(struct em28xx *dev) struct urb *urb; int j, k; - dev->adev.transfer_buffer[i] = kmalloc(sb_size, GFP_ATOMIC); + dev->adev.transfer_buffer[i] = kmalloc(sb_size, GFP_KERNEL); if (!dev->adev.transfer_buffer[i]) return -ENOMEM; memset(dev->adev.transfer_buffer[i], 0x80, sb_size); - urb = usb_alloc_urb(EM28XX_NUM_AUDIO_PACKETS, GFP_ATOMIC); + urb = usb_alloc_urb(EM28XX_NUM_AUDIO_PACKETS, GFP_KERNEL); if (!urb) { em28xx_errdev("usb_alloc_urb failed!\n"); for (j = 0; j < i; j++) { @@ -212,7 +212,7 @@ static int em28xx_init_audio_isoc(struct em28xx *dev) } for (i = 0; i < EM28XX_AUDIO_BUFS; i++) { - errCode = usb_submit_urb(dev->adev.urb[i], GFP_ATOMIC); + errCode = usb_submit_urb(dev->adev.urb[i], GFP_KERNEL); if (errCode) { em28xx_errdev("submit of audio urb failed\n"); em28xx_deinit_isoc_audio(dev); diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c index bed07a6..c5a2c4b 100644 --- a/drivers/media/usb/em28xx/em28xx-core.c +++ b/drivers/media/usb/em28xx/em28xx-core.c @@ -1166,7 +1166,7 @@ int em28xx_init_isoc(struct em28xx *dev, enum em28xx_mode mode, /* submit urbs and enables IRQ */ for (i = 0; i < isoc_bufs->num_bufs; i++) { - rc = usb_submit_urb(isoc_bufs->urb[i], GFP_ATOMIC); + rc = usb_submit_urb(isoc_bufs->urb[i], GFP_KERNEL); if (rc) { em28xx_err("submit of urb %i failed (error=%i)\n", i, rc);