Re: [alsa-devel] [PATCH 0/5] PCM mmap (temporary) fixes for non-coherent architectures
At Fri, 1 Jan 2010 20:31:30 +0100, Andreas Mohr wrote:
Hi,
I've tried this patch set (with the typo-corrected part 4) on my ASUS WL-500gP v2 MIPSEL via a backport to 2.6.31.9, but all I get is a small blip of the sound I wanted to play, and then the system is fubar (I believe just the same thing as what happened without having this patch applied).
As I mentioned in the previous followup, if your device is a USB-audio, the patch doesn't help because it's for devices with buffers using dma_alloc_coherent(). For USB-audio, it uses vmalloc for an intermediate buffer. Maybe this should be changed to dma_*() stuff for such architectures.
Nevertheless, I don't know whether the crash is related with the audio part...
Takashi
At Tue, 12 Jan 2010 08:02:36 +0100, I wrote:
At Fri, 1 Jan 2010 20:31:30 +0100, Andreas Mohr wrote:
Hi,
I've tried this patch set (with the typo-corrected part 4) on my ASUS WL-500gP v2 MIPSEL via a backport to 2.6.31.9, but all I get is a small blip of the sound I wanted to play, and then the system is fubar (I believe just the same thing as what happened without having this patch applied).
As I mentioned in the previous followup, if your device is a USB-audio, the patch doesn't help because it's for devices with buffers using dma_alloc_coherent(). For USB-audio, it uses vmalloc for an intermediate buffer. Maybe this should be changed to dma_*() stuff for such architectures.
A quick patch below (totally untested!) might do that. It's passing the device struct blindly, so not sure whether this would actually work for all dma_alloc_coherent().
Takashi
--- diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c index 9edef46..6c82026 100644 --- a/sound/usb/usbaudio.c +++ b/sound/usb/usbaudio.c @@ -734,7 +734,7 @@ static void snd_complete_sync_urb(struct urb *urb) } }
- +#ifdef USBAUDIO_VMALLOC_BUFFER /* get the physical page pointer at the given offset */ static struct page *snd_pcm_get_vmalloc_page(struct snd_pcm_substream *subs, unsigned long offset) @@ -769,6 +769,24 @@ static int snd_pcm_free_vmalloc_buffer(struct snd_pcm_substream *subs) return 0; }
+#define preallocate_buffer(chip, pcm, stream) /* NOP */ + +#else +#define snd_pcm_get_vmalloc_page NULL +#define snd_pcm_alloc_vmalloc_buffer snd_pcm_lib_malloc_pages +#define snd_pcm_free_vmalloc_buffer snd_pcm_lib_free_pages + +static int preallocate_buffer(struct snd_usb_audio *chip, struct snd_pcm *pcm, + int stream) +{ + struct snd_pcm_substream *subs = pcm->streams[stream].substream; + if (!subs) + return 0; + return snd_pcm_lib_preallocate_pages(subs, SNDRV_DMA_TYPE_DEV, + chip->card->dev, + 1024 * 64, 1024 * 1024); +} +#endif
/* * unlink active urbs. @@ -2328,6 +2346,7 @@ static int add_audio_endpoint(struct snd_usb_audio *chip, int stream, struct aud err = snd_pcm_new_stream(as->pcm, stream, 1); if (err < 0) return err; + preallocate_buffer(chip, as->pcm, stream); init_substream(as, stream, fp); return 0; } @@ -2356,6 +2375,7 @@ static int add_audio_endpoint(struct snd_usb_audio *chip, int stream, struct aud else strcpy(pcm->name, "USB Audio");
+ preallocate_buffer(chip, pcm, stream); init_substream(as, stream, fp);
list_add(&as->list, &chip->pcm_list);
On Wed, Jan 13, 2010 at 10:07:32AM +0100, Takashi Iwai wrote:
As I mentioned in the previous followup, if your device is a USB-audio, the patch doesn't help because it's for devices with buffers using dma_alloc_coherent(). For USB-audio, it uses vmalloc for an intermediate buffer. Maybe this should be changed to dma_*() stuff for such architectures.
A quick patch below (totally untested!) might do that. It's passing the device struct blindly, so not sure whether this would actually work for all dma_alloc_coherent().
Thanks a lot, tested, but AFAICS there isn't much of a change unfortunately (log below). Note that the old snd-usb-audio.ko did contain snd_pcm_get_vmalloc_page(), and the new one (put in the correct kernel version dir and depmod -a) doesn't, thus the patch was applied and did make it to the binary side, and it did get loaded correctly upon plugging I think.
Would one also want strace/ltrace output of the userspace side of things? (likely rather useless, except for perhaps nailing that it does crash where we think it crashes or so)
Frankly I'm still pretty much in uninformed shape concerning this mmap pcm buffer issue, would need to take quite a bit more time for research in order to be able to take part in the discussion in a productive way ;)
Thanks,
Andreas Mohr
# cat /usr/local/bin/audio_test.sh #!/bin/sh
# better make sure... sync sleep 1
aplay /usr/local/sounds/attention
[LOCKUP]
$ ../netconsole.sh kobject: 'ep_01' (81f70090): kobject_add_internal: parent: '2-1.1.1:1.1', set: 'devices' kobject: 'ep_01' (81f70090): kobject_uevent_env kobject: 'ep_01' (81f70090): kobject_uevent_env: filter function caused the event to drop! setting usb interface 1:1 Instruction bus error, epc == 2ab4f178, ra == 80000018 kobject: 'ep_01' (81f70090): kobject_uevent_env kobject: 'ep_01' (81f70090): kobject_uevent_env: filter function caused the event to drop! kobject: 'ep_01' (81f70090): kobject_cleanup kobject: 'ep_01' (81f70090): calling ktype release kobject: 'ep_01': free name EHCI_DIS: hcd 81dd7080 ep 81604800 qh (null) (#01) Instruction bus error, epc == 8003475c, ra == 80000018 Oops[#1]: Cpu 0 $ 0 : 00000000 1000d001 00000000 80000000 $ 4 : 81d30838 81e57ac0 00000000 00000000 $ 8 : 00000000 00000000 81040000 81ec8000 $12 : 81d37868 80340000 81d37868 0000000a $16 : 00000000 7fa911e8 00000538 81d30838 $20 : 0000000a 81f0def8 20000000 fffffff6 $24 : 00000000 801874c0 $28 : 81f0c000 81f0de40 00000001 80000018 Hi : 00000000 Lo : 00000000 epc : 8003475c wait_consider_task+0x49c/0xe20 Not tainted ra : 80000018 0x80000018 Status: 1000d003 KERNEL EXL IE Cause : 00800018 PrId : 00029029 (Broadcom BCM3302) Modules linked in: snd_usb_audio snd_pcm_oss snd_mixer_oss snd_pcm snd_timer evdev snd_page_alloc snd_usb_lib snd_rawmidi snd_seq_device snd_hwdep usbhid hid snd input_core soundcore ipv6 arc4 ecb cryptomgr aead pcompress crypto_blkcipher crypto_hash crypto_algapi b43 ftdi_sio mac80211 cfg80211 usbserial Process audio_test.sh (pid: 1333, threadinfo=81f0c000, task=81d37838, tls=00000000) Stack : 8033dab8 80027e24 81e8488c 802b89e0 8033c000 81d37838 00000000 8000ace0 00000000 00000000 81e57e60 80018238 81d30838 81d37838 00000000 81d3794c 81f0def8 ffffffff 20000000 fffffff6 00000001 800351b4 00000004 801c7cf8 7fa911a8 81db5870 00000000 81d37838 8002d0c4 81e57ac8 81e57ac8 81d37838 00000000 00000000 7fa911e8 00000000 0051f56c 00000000 00440000 00525790 ... Call Trace: [<8003475c>] wait_consider_task+0x49c/0xe20 [<800351b4>] do_wait+0xd4/0x340 [<800354e0>] sys_wait4+0xc0/0xec [<800031f0>] stack_done+0x20/0x3c
Code: 00431024 14400251 00000000 <ae340000> 16000051 8eb1000c 12200051 8fa30020 0c002bc1 Disabling lock debugging due to kernel taint Instruction bus error, epc == 80004dd8, ra == 80000018 Oops[#2]: Cpu 0 $ 0 : 00000000 1000d000 00000000 00000000 $ 4 : 7ff0dc60 81c0ddd0 00000000 1000d001 $ 8 : 00000000 00000000 00000000 81f0c000 $12 : 81c084b0 003d0900 81c084b0 00000000 $16 : 00000004 00000000 81c0ddc0 81c0ddc0 $20 : 7ff0dc60 00000000 81c0ddcc 00000000 $24 : 00000000 801874c0 $28 : 81c0c000 81c0dd98 00000001 80000018 Hi : 0000007f Lo : 3d391e00 epc : 80004dd8 __copy_user+0xd4/0x2bc Tainted: G D ra : 80000018 0x80000018 Status: 1000d003 KERNEL EXL IE Cause : 00800018 PrId : 00029029 (Broadcom BCM3302) Modules linked in: snd_usb_audio snd_pcm_oss snd_mixer_oss snd_pcm snd_timer evdev snd_page_alloc snd_usb_lib snd_rawmidi snd_seq_device snd_hwdep usbhid hid snd input_core soundcore ipv6 arc4 ecb cryptomgr aead pcompress crypto_blkcipher crypto_hash crypto_algapi b43 ftdi_sio mac80211 cfg80211 usbserial Process init (pid: 1, threadinfo=81c0c000, task=81c08480, tls=00000000) Stack : 00000000 81c0dda8 81c0df00 80350fb0 81c0ddc0 81c0ddc4 81c0ddc8 81c0ddcc 81c0ddd0 81c0ddd4 00000400 00000000 00000000 00000000 00000000 00000000 00000000 00000000 81f04000 ffffff9c 81c0dea8 0044a234 7ff0e048 8009b864 00000001 81c0dea8 00000001 81f04000 ffffff9c 800a2d18 00000003 00000002 00000003 00000003 0000000d 00000000 00000000 00000000 000000cc 00001180 ... Call Trace: [<80004dd8>] __copy_user+0xd4/0x2bc
Code: 8ca80000 24a50004 24c6fffc <ac880000> 1706fffb 24840004 10c00040 00864821 240a0020 Instruction bus error, epc == 8003475c, ra == 80000018 Oops[#3]: Cpu 0 $ 0 : 00000000 1000d001 00000000 80000000 $ 4 : 81d37838 80415e00 00000000 00000000 $ 8 : 00000000 00000000 81040000 81f0c000 $12 : 80484868 80340000 80484868 0000000b $16 : 00000000 7febff60 00000535 81d37838 $20 : 0000000b 81e2bef8 20000000 fffffff6 $24 : 00000000 80018ff0 $28 : 81e2a000 81e2be40 00000001 80000018 Hi : 00000000 Lo : 00000000 epc : 8003475c wait_consider_task+0x49c/0xe20 Tainted: G D ra : 80000018 0x80000018 Status: 1000d003 KERNEL EXL IE Cause : 00800018 PrId : 00029029 (Broadcom BCM3302) Modules linked in: snd_usb_audio snd_pcm_oss snd_mixer_oss snd_pcm snd_timer evdev snd_page_alloc snd_usb_lib snd_rawmidi snd_seq_device snd_hwdep usbhid hid snd input_core soundcore ipv6 arc4 ecb cryptomgr aead pcompress crypto_blkcipher crypto_hash crypto_algapi b43 ftdi_sio mac80211 cfg80211 usbserial Process bash (pid: 1175, threadinfo=81e2a000, task=80484838, tls=00000000) Stack : 8033dab8 80027e24 81f18390 00002a84 81d37838 80484838 81e57e60 8000ace0 00000000 00000000 80047476 0051f510 81d37838 80484838 00000000 8048494c 81e2bef8 ffffffff 20000000 fffffff6 00000001 800351b4 81e8a1e0 00000008 81e8a0d4 81d37870 00000000 80484838 8002d0c4 80415e08 80415e08 80484838 0000000a 00000000 7febff60 00000000 0051f56c 00000000 00440000 00525790 ... Call Trace: [<8003475c>] wait_consider_task+0x49c/0xe20 [<800351b4>] do_wait+0xd4/0x340 [<800354e0>] sys_wait4+0xc0/0xec [<800031f0>] stack_done+0x20/0x3c
Code: 00431024 14400251 00000000 <ae340000> 16000051 8eb1000c 12200051 8fa30020 0c002bc1 Instruction bus error, epc == 80096fa0, ra == 80000018 Oops[#4]: Cpu 0 $ 0 : 00000000 1000d000 c0180002 00000002 $ 4 : 00000001 803b5514 00000001 81e24000 $ 8 : 80351000 00080000 81040000 81e2a000 $12 : 00000000 07de2900 ffffffff 00000000 $16 : 00000001 81e24fa0 2abe8000 003cbf03 $20 : 2abe9000 0119a613 00000000 00000000 $24 : 00000000 80018ff0 $28 : 81c0c000 81c0db48 00000000 80000018 Hi : 00000000 Lo : 00000000 epc : 80096fa0 swap_info_get+0x74/0xfc Tainted: G D ra : 80000018 0x80000018 Status: 1000d003 KERNEL EXL IE Cause : 00800018 PrId : 00029029 (Broadcom BCM3302) Modules linked in: snd_usb_audio snd_pcm_oss snd_mixer_oss snd_pcm snd_timer evdev snd_page_alloc snd_usb_lib snd_rawmidi snd_seq_device snd_hwdep usbhid hid snd input_core soundcore ipv6 arc4 ecb cryptomgr aead pcompress crypto_blkcipher crypto_hash crypto_algapi b43 ftdi_sio mac80211 cfg80211 usbserial Process init (pid: 1, threadinfo=81c0c000, task=81c08480, tls=00000000) Stack : ffffffff 800736a0 80002000 80000600 80350fd0 80099498 00002000 81023340 81e24f9c 2abe7000 00002000 81e24fa0 2abe8000 80088a30 81e0da9c 81e1e000 8037f840 81e1e034 2abe8fff 8033d9c0 81e1e000 81e1f2a8 81e1f2a8 2abe9000 00000000 00000001 81e0da9c 81e1e000 8037f840 81e1e034 81c08480 00000000 00000001 00000000 00000001 8008db1c 81c0dbf0 81e26000 00000000 ffffffff ... Call Trace: [<80096fa0>] swap_info_get+0x74/0xfc [<80099498>] free_swap_and_cache+0x1c/0x218 [<80088a30>] unmap_vmas+0x418/0x63c [<8008db1c>] exit_mmap+0xb8/0x148 [<8002e3c4>] mmput+0xc0/0x1d8 [<800333e8>] exit_mm+0x260/0x298 [<800357cc>] do_exit+0x1cc/0x688 [<80014658>] nmi_exception_handler+0x0/0x34
Code: 00041840 8ca20020 00431021 <94440000> 1480001d 8fbf0014 3c048030 3c05802c 24a5f280 Fixing recursive fault but reboot is needed! Instruction bus error, epc == 80004dd8, ra == 80000018 Oops[#5]: Cpu 0 $ 0 : 00000000 1000d000 00000000 00000004 $ 4 : 004c2a30 81e3ddd0 00000000 1000d001 $ 8 : 00000080 00000000 00000000 81e2a000 $12 : 81d66868 00000000 81d66868 00000000 $16 : 00000004 00000001 81e3ddc0 81e3ddc0 $20 : 004c2a30 004c7c98 81e3ddcc 00000000 $24 : 00000000 80181208 $28 : 81e3c000 81e3dd98 004b0000 80000018 Hi : 00000000 Lo : 00000000 epc : 80004dd8 __copy_user+0xd4/0x2bc Tainted: G D ra : 80000018 0x80000018 Status: 1000d003 KERNEL EXL IE Cause : 00800018 PrId : 00029029 (Broadcom BCM3302) Modules linked in: snd_usb_audio snd_pcm_oss snd_mixer_oss snd_pcm snd_timer evdev snd_page_alloc snd_usb_lib snd_rawmidi snd_seq_device snd_hwdep usbhid hid snd input_core soundcore ipv6 arc4 ecb cryptomgr aead pcompress crypto_blkcipher crypto_hash crypto_algapi b43 ftdi_sio mac80211 cfg80211 usbserial Process sshd (pid: 1173, threadinfo=81e3c000, task=81d66838, tls=00000000) Stack : 0041663c 81e3dda8 00000000 80200478 81e3ddc0 81e3ddc4 81e3ddc8 81e3ddcc 81e3ddd0 81e3ddd4 00000098 00000000 00000000 00000080 00000000 00000000 00000000 00000000 81e3de20 00000001 00000000 00000000 00000040 81e3de28 81e3de28 fffffdee 81e3de20 8009e530 00000000 814a5a20 81f5d8ec 81ed3900 00000000 00000000 004bd538 00000038 81d41900 8017a668 00000000 00000001 ... Call Trace: [<80004dd8>] __copy_user+0xd4/0x2bc
Code: 8ca80000 24a50004 24c6fffc <ac880000> 1706fffb 24840004 10c00040 00864821 240a0020 Instruction bus error, epc == 80011530, ra == 80000018 Oops[#6]: Cpu 0 $ 0 : 00000000 1000d001 24020000 80000000 $ 4 : 7fb160e0 24021017 00000278 81c6ec2c $ 8 : 800125cc 8155fe80 ffffffff ffffffff $12 : 00000000 80340000 81c6e8b0 0000000b $16 : 00000000 00000000 7fb160d0 8155ff30 $20 : 7fb160e8 7fb160e0 81c6ec2c 00000012 $24 : 00000000 8025e170 $28 : 8155e000 8155fe10 8155fe80 80000018 Hi : 00000000 Lo : 00000000 epc : 80011530 install_sigtramp+0x20/0x54 Tainted: G D ra : 80000018 0x80000018 Status: 1000d003 KERNEL EXL IE Cause : 00800018 PrId : 00029029 (Broadcom BCM3302) Modules linked in: snd_usb_audio snd_pcm_oss snd_mixer_oss snd_pcm snd_timer evdev snd_page_alloc snd_usb_lib snd_rawmidi snd_seq_device snd_hwdep usbhid hid snd input_core soundcore ipv6 arc4 ecb cryptomgr aead pcompress crypto_blkcipher crypto_hash crypto_algapi b43 ftdi_sio mac80211 cfg80211 usbserial Process sshd (pid: 1100, threadinfo=8155e000, task=81c6e880, tls=00000000) Stack : 8155ff30 8155fe98 8167f000 8169f004 00000009 8155ff30 00000012 8001263c 81d58b18 81d58b18 81c59808 800b212c 8155ff30 00000012 8155fe80 81c6ec2c 8155fe98 ffffffff 004b352c 00000000 00000004 800116bc 8167f1e0 8155fe80 8155ff30 8155fea8 00000010 81d58b18 00000000 0040ac18 00000000 00000000 00000000 00000000 00000012 00040002 00000000 00000495 00000000 0000000b ... Call Trace: [<80011530>] install_sigtramp+0x20/0x54 [<8001263c>] setup_frame+0x70/0x110 [<800116bc>] do_notify_resume+0x158/0x428 [<800015f0>] work_notifysig+0xc/0x14
Code: afbf001c 00a22821 02008821 <ac850000> 2402000c ac820004 3c038038 8c620038 0040f809 Instruction bus error, epc == 2ac458ec, ra == 80000018
At Thu, 14 Jan 2010 08:46:38 +0100, Andreas Mohr wrote:
On Wed, Jan 13, 2010 at 10:07:32AM +0100, Takashi Iwai wrote:
As I mentioned in the previous followup, if your device is a USB-audio, the patch doesn't help because it's for devices with buffers using dma_alloc_coherent(). For USB-audio, it uses vmalloc for an intermediate buffer. Maybe this should be changed to dma_*() stuff for such architectures.
A quick patch below (totally untested!) might do that. It's passing the device struct blindly, so not sure whether this would actually work for all dma_alloc_coherent().
Thanks a lot, tested, but AFAICS there isn't much of a change unfortunately (log below).
Of course, not for the crash. The patch was for improving the sound quality (if any).
Takashi
A quick patch below (totally untested!) might do that. It's passing the device struct blindly, so not sure whether this would actually work for all dma_alloc_coherent().
On archs that have dma_ops such as powerpc (but I think x86 too nowadays) you cannot use the USB device for dma_* operations. You need to get up to the host controller device...
It -might- be worth looking at adding code to the USB stack to propagate the parent device dma_ops down to USB devices... hard to tell.
Cheers, Ben.
Takashi
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c index 9edef46..6c82026 100644 --- a/sound/usb/usbaudio.c +++ b/sound/usb/usbaudio.c @@ -734,7 +734,7 @@ static void snd_complete_sync_urb(struct urb *urb) } }
+#ifdef USBAUDIO_VMALLOC_BUFFER /* get the physical page pointer at the given offset */ static struct page *snd_pcm_get_vmalloc_page(struct snd_pcm_substream *subs, unsigned long offset) @@ -769,6 +769,24 @@ static int snd_pcm_free_vmalloc_buffer(struct snd_pcm_substream *subs) return 0; }
+#define preallocate_buffer(chip, pcm, stream) /* NOP */
+#else +#define snd_pcm_get_vmalloc_page NULL +#define snd_pcm_alloc_vmalloc_buffer snd_pcm_lib_malloc_pages +#define snd_pcm_free_vmalloc_buffer snd_pcm_lib_free_pages
+static int preallocate_buffer(struct snd_usb_audio *chip, struct snd_pcm *pcm,
int stream)+{
- struct snd_pcm_substream *subs = pcm->streams[stream].substream;
- if (!subs)
return 0;- return snd_pcm_lib_preallocate_pages(subs, SNDRV_DMA_TYPE_DEV,
chip->card->dev,1024 * 64, 1024 * 1024);+} +#endif
/*
- unlink active urbs.
@@ -2328,6 +2346,7 @@ static int add_audio_endpoint(struct snd_usb_audio *chip, int stream, struct aud err = snd_pcm_new_stream(as->pcm, stream, 1); if (err < 0) return err;
preallocate_buffer(chip, as->pcm, stream);@@ -2356,6 +2375,7 @@ static int add_audio_endpoint(struct snd_usb_audio *chip, int stream, struct aud else strcpy(pcm->name, "USB Audio");
preallocate_buffer(chip, pcm, stream); init_substream(as, stream, fp);
list_add(&as->list, &chip->pcm_list);
At Fri, 15 Jan 2010 14:28:02 +1100, Benjamin Herrenschmidt wrote:
A quick patch below (totally untested!) might do that. It's passing the device struct blindly, so not sure whether this would actually work for all dma_alloc_coherent().
On archs that have dma_ops such as powerpc (but I think x86 too nowadays) you cannot use the USB device for dma_* operations. You need to get up to the host controller device...
Yep, I don't think this being a proper fix, too.
It -might- be worth looking at adding code to the USB stack to propagate the parent device dma_ops down to USB devices... hard to tell.
Or we may simply need to drop the mmap support on such architectures...
thanks,
Takashi
Cheers, Ben.
Takashi
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c index 9edef46..6c82026 100644 --- a/sound/usb/usbaudio.c +++ b/sound/usb/usbaudio.c @@ -734,7 +734,7 @@ static void snd_complete_sync_urb(struct urb *urb) } }
+#ifdef USBAUDIO_VMALLOC_BUFFER /* get the physical page pointer at the given offset */ static struct page *snd_pcm_get_vmalloc_page(struct snd_pcm_substream *subs, unsigned long offset) @@ -769,6 +769,24 @@ static int snd_pcm_free_vmalloc_buffer(struct snd_pcm_substream *subs) return 0; }
+#define preallocate_buffer(chip, pcm, stream) /* NOP */
+#else +#define snd_pcm_get_vmalloc_page NULL +#define snd_pcm_alloc_vmalloc_buffer snd_pcm_lib_malloc_pages +#define snd_pcm_free_vmalloc_buffer snd_pcm_lib_free_pages
+static int preallocate_buffer(struct snd_usb_audio *chip, struct snd_pcm *pcm,
int stream)+{
- struct snd_pcm_substream *subs = pcm->streams[stream].substream;
- if (!subs)
return 0;- return snd_pcm_lib_preallocate_pages(subs, SNDRV_DMA_TYPE_DEV,
chip->card->dev,1024 * 64, 1024 * 1024);+} +#endif
/*
- unlink active urbs.
@@ -2328,6 +2346,7 @@ static int add_audio_endpoint(struct snd_usb_audio *chip, int stream, struct aud err = snd_pcm_new_stream(as->pcm, stream, 1); if (err < 0) return err;
preallocate_buffer(chip, as->pcm, stream);@@ -2356,6 +2375,7 @@ static int add_audio_endpoint(struct snd_usb_audio *chip, int stream, struct aud else strcpy(pcm->name, "USB Audio");
preallocate_buffer(chip, pcm, stream); init_substream(as, stream, fp);
list_add(&as->list, &chip->pcm_list);
On Fri, 2010-01-15 at 07:43 +0100, Takashi Iwai wrote:
It -might- be worth looking at adding code to the USB stack to
propagate
the parent device dma_ops down to USB devices... hard to tell.
Or we may simply need to drop the mmap support on such architectures...
Nah, that would suck since that includes x86 nowadays :-)
I think you probably need to separate the struct device * used for DMA (it could be default be the same as the "main" struct device tho or it could default to NULL which means no mmap support).
USB could (if not already) provide an accessor to obtain the HC's struct device for such mappings. We'll have to discuss that with Alan Stern I suppose.
The USB Audio or similar drivers could then use that accessors to fill up Alsa's dma_device field to replace the "default".
Cheers, Ben.
At Fri, 15 Jan 2010 17:50:49 +1100, Benjamin Herrenschmidt wrote:
On Fri, 2010-01-15 at 07:43 +0100, Takashi Iwai wrote:
It -might- be worth looking at adding code to the USB stack to
propagate
the parent device dma_ops down to USB devices... hard to tell.
Or we may simply need to drop the mmap support on such architectures...
Nah, that would suck since that includes x86 nowadays :-)
Ah, no, I meant about non-coherent architectures that can't use vmalloc pages as the intermediate buffer. Dropping mmap for x86 would be a big regression ;)
I think you probably need to separate the struct device * used for DMA (it could be default be the same as the "main" struct device tho or it could default to NULL which means no mmap support).
USB could (if not already) provide an accessor to obtain the HC's struct device for such mappings. We'll have to discuss that with Alan Stern I suppose.
The USB Audio or similar drivers could then use that accessors to fill up Alsa's dma_device field to replace the "default".
The situation of usb-audio is, unfortunately, a bit more complex because the driver needs a continuous ring-buffer. The packet data are copied from that intermediate buffer on demand.
This isn't efficient, but the continuous ring-buffer is demanded by the current API design exported as mmap.
thanks,
Takashi
Hi,
On Tue, Jan 12, 2010 at 08:02:36AM +0100, Takashi Iwai wrote:
At Fri, 1 Jan 2010 20:31:30 +0100, Andreas Mohr wrote:
Hi,
I've tried this patch set (with the typo-corrected part 4) on my ASUS WL-500gP v2 MIPSEL via a backport to 2.6.31.9, but all I get is a small blip of the sound I wanted to play, and then the system is fubar (I believe just the same thing as what happened without having this patch applied).
Crap, you already managed to beat me to my own reply! ;) (I'll try your patch in the other mail _ASAP_)
As I mentioned in the previous followup, if your device is a USB-audio, the patch doesn't help because it's for devices with buffers using dma_alloc_coherent(). For USB-audio, it uses vmalloc for an intermediate buffer. Maybe this should be changed to dma_*() stuff for such architectures.
I've been searching the mailing list postings up and down, but I couldn't deduce anything to that effect from that content (but I'm mailing list-externally - maybe I just really didn't find the correct posting or there was a threading split)
Nevertheless, I don't know whether the crash is related with the audio part...
Yes, I wasn't fully pointing at the crash being caused by insufficient patches in that area either... (but I haven't fully investigated these OOPSes yet)
Thanks a lot for your new test patch,
Andreas Mohr
participants (3)
-
Andreas Mohr -
Benjamin Herrenschmidt -
Takashi Iwai