[alsa-devel] [PATCH] MIPS: Fixups of ALSA memory maps
Hi, All
Seems this is MIPS specific, but it's not that easy to move this patch into the arch/mips part, So, any better solution?
Thanks & Regards, Wu Zhangjin
------------------------
The user application mmap audio dma regions must be dma-coherent. This patch fix it.
Without this patch, artsd will fail on boot, and mplayer will exit with "Segmentation fault". (this happens on YeeLoong netbook, fuloong2f mini pc with snd_cs5535 audio card)
This is originally from the to-mips branch of http://dev.lemote.com/code/linux_loongson, and contributed by Yanhua from Lemote Inc.
Reported-by: qiaochong qiaochong@gmail.com Signed-off-by: Wu Zhangjin wuzj@lemote.com --- sound/core/pcm_native.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index ab73edf..2779b9a 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -3087,7 +3087,11 @@ static int snd_pcm_mmap_data_fault(struct vm_area_struct *area, return VM_FAULT_SIGBUS; } else { vaddr = runtime->dma_area + offset; +#if defined(__mips__) && defined(CONFIG_DMA_NONCOHERENT) + page = virt_to_page(CAC_ADDR(vaddr)); +#else page = virt_to_page(vaddr); +#endif } get_page(page); vmf->page = page; @@ -3202,6 +3206,11 @@ static int snd_pcm_mmap(struct file *file, struct vm_area_struct *area) if (PCM_RUNTIME_CHECK(substream)) return -ENXIO;
+#if defined(__mips__) && defined(CONFIG_DMA_NONCOHERENT) + /* all mmap using uncached mode */ + area->vm_page_prot = pgprot_noncached(area->vm_page_prot); + area->vm_flags |= (VM_RESERVED | VM_IO); +#endif offset = area->vm_pgoff << PAGE_SHIFT; switch (offset) { case SNDRV_PCM_MMAP_OFFSET_STATUS:
On Tue, Nov 17, 2009 at 12:48:14AM +0800, Wu Zhangjin wrote:
Seems this is MIPS specific, but it's not that easy to move this patch into the arch/mips part, So, any better solution?
Thanks & Regards, Wu Zhangjin
The user application mmap audio dma regions must be dma-coherent. This patch fix it.
Without this patch, artsd will fail on boot, and mplayer will exit with "Segmentation fault". (this happens on YeeLoong netbook, fuloong2f mini pc with snd_cs5535 audio card)
This is originally from the to-mips branch of http://dev.lemote.com/code/linux_loongson, and contributed by Yanhua from Lemote Inc.
Reported-by: qiaochong qiaochong@gmail.com Signed-off-by: Wu Zhangjin wuzj@lemote.com
This issue is an old ghost still around, see:
http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=20060124.13283...
which is a superset of your proposed patch and which itself is refering to an even older posting from 2003:
http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=20030523215935...
The #ifdef'ed solution doesn't cut it for sure. Let's see what better we can find ...
Ralf
At Mon, 16 Nov 2009 18:06:41 +0100, Ralf Baechle wrote:
On Tue, Nov 17, 2009 at 12:48:14AM +0800, Wu Zhangjin wrote:
Seems this is MIPS specific, but it's not that easy to move this patch into the arch/mips part, So, any better solution?
Thanks & Regards, Wu Zhangjin
The user application mmap audio dma regions must be dma-coherent. This patch fix it.
Without this patch, artsd will fail on boot, and mplayer will exit with "Segmentation fault". (this happens on YeeLoong netbook, fuloong2f mini pc with snd_cs5535 audio card)
This is originally from the to-mips branch of http://dev.lemote.com/code/linux_loongson, and contributed by Yanhua from Lemote Inc.
Reported-by: qiaochong qiaochong@gmail.com Signed-off-by: Wu Zhangjin wuzj@lemote.com
This issue is an old ghost still around, see:
http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=20060124.13283...
which is a superset of your proposed patch and which itself is refering to an even older posting from 2003:
http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=20030523215935...
The #ifdef'ed solution doesn't cut it for sure. Let's see what better we can find ...
Indeed. My preference option is to deploy dma_mmap_coherent() to possible architectures and use it commonly in the ALSA core code.
But, as a temporary workaround, I'm fine with ifdef until the API is defined...
thanks,
Takashi
On Mon, Nov 16, 2009 at 06:14:14PM +0100, Takashi Iwai wrote:
Seems this is MIPS specific, but it's not that easy to move this patch into the arch/mips part, So, any better solution?
Thanks & Regards, Wu Zhangjin
The user application mmap audio dma regions must be dma-coherent. This patch fix it.
Without this patch, artsd will fail on boot, and mplayer will exit with "Segmentation fault". (this happens on YeeLoong netbook, fuloong2f mini pc with snd_cs5535 audio card)
This is originally from the to-mips branch of http://dev.lemote.com/code/linux_loongson, and contributed by Yanhua from Lemote Inc.
Reported-by: qiaochong qiaochong@gmail.com Signed-off-by: Wu Zhangjin wuzj@lemote.com
This issue is an old ghost still around, see:
http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=20060124.13283...
which is a superset of your proposed patch and which itself is refering to an even older posting from 2003:
http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=20030523215935...
The #ifdef'ed solution doesn't cut it for sure. Let's see what better we can find ...
Indeed. My preference option is to deploy dma_mmap_coherent() to possible architectures and use it commonly in the ALSA core code.
But, as a temporary workaround, I'm fine with ifdef until the API is defined...
There is a MIPS platform which may be based on a variety of system controllers only one of which supports cache coherency. So we want to deciede at runtime not at compile time.
Ralf
At Tue, 17 Nov 2009 00:48:14 +0800, Wu Zhangjin wrote:
Hi, All
Seems this is MIPS specific, but it's not that easy to move this patch into the arch/mips part, So, any better solution?
Actually, this has been a looong-standing problem. I have a series of patches to fix these issues, but it's more intensively involved with dma_*() functions.
The patches can be found in test/dma-fix branch of sound GIT tree. git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git test/dma-fix
This basically adds dma_mmap_coherent() function to feasible architectures, which is already implemented for ARM, so far.
thanks,
Takashi
On Mon, Nov 16, 2009 at 06:12:22PM +0100, Takashi Iwai wrote:
Actually, this has been a looong-standing problem. I have a series of patches to fix these issues, but it's more intensively involved with dma_*() functions.
The patches can be found in test/dma-fix branch of sound GIT tree. git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git test/dma-fix
This basically adds dma_mmap_coherent() function to feasible architectures, which is already implemented for ARM, so far.
Cool - but needs a little further tweaking to work right. That's a solution which will use uncached accesses on all MIPS systems.
IP27/IP35-family machines will explode when you try that. Eventually the cache coherency logic will notice that cache, directory caches and memory have become inconsistent and bombard the CPU with a bunch of nasty exceptions.
For cache-coherent machines otoh it's a big waste of performance.
int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t handle, size_t size) { struct page *pg;
if (!plat_device_is_coherent(dev)) vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); cpu_addr = (void *)dma_addr_to_virt(handle); pg = virt_to_page(cpu_addr);
return remap_pfn_range(vma, vma->vm_start, page_to_pfn(pg) + vma->vm_pgoff, size, vma->vm_page_prot); } EXPORT_SYMBOL(dma_mmap_coherent);
Thomas - you're the IP28 specialist. Would the plat_device_is_coherent() above have to become a cpu_is_noncoherent_r10000() call? Any further nasties?
Ralf
At Mon, 16 Nov 2009 18:43:24 +0100, Ralf Baechle wrote:
On Mon, Nov 16, 2009 at 06:12:22PM +0100, Takashi Iwai wrote:
Actually, this has been a looong-standing problem. I have a series of patches to fix these issues, but it's more intensively involved with dma_*() functions.
The patches can be found in test/dma-fix branch of sound GIT tree. git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git test/dma-fix
This basically adds dma_mmap_coherent() function to feasible architectures, which is already implemented for ARM, so far.
Cool - but needs a little further tweaking to work right. That's a solution which will use uncached accesses on all MIPS systems.
IP27/IP35-family machines will explode when you try that. Eventually the cache coherency logic will notice that cache, directory caches and memory have become inconsistent and bombard the CPU with a bunch of nasty exceptions.
OK, that's really bad.
For cache-coherent machines otoh it's a big waste of performance.
int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t handle, size_t size) { struct page *pg;
if (!plat_device_is_coherent(dev)) vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); cpu_addr = (void *)dma_addr_to_virt(handle); pg = virt_to_page(cpu_addr);
return remap_pfn_range(vma, vma->vm_start, page_to_pfn(pg) + vma->vm_pgoff, size, vma->vm_page_prot);} EXPORT_SYMBOL(dma_mmap_coherent);
Thomas - you're the IP28 specialist. Would the plat_device_is_coherent() above have to become a cpu_is_noncoherent_r10000() call? Any further nasties?
Thanks for checking!
thanks,
Takashi
On Tue, Nov 17, 2009 at 10:29:10AM +0100, Takashi Iwai wrote:
Actually, this has been a looong-standing problem. I have a series of patches to fix these issues, but it's more intensively involved with dma_*() functions.
The patches can be found in test/dma-fix branch of sound GIT tree. git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git test/dma-fix
This basically adds dma_mmap_coherent() function to feasible architectures, which is already implemented for ARM, so far.
Cool - but needs a little further tweaking to work right. That's a solution which will use uncached accesses on all MIPS systems.
IP27/IP35-family machines will explode when you try that. Eventually the cache coherency logic will notice that cache, directory caches and memory have become inconsistent and bombard the CPU with a bunch of nasty exceptions.
OK, that's really bad.
Hardware designers do such things to you. Often even for a reason.
For cache-coherent machines otoh it's a big waste of performance.
int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t handle, size_t size) { struct page *pg;
if (!plat_device_is_coherent(dev)) vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); cpu_addr = (void *)dma_addr_to_virt(handle); pg = virt_to_page(cpu_addr);
return remap_pfn_range(vma, vma->vm_start, page_to_pfn(pg) + vma->vm_pgoff, size, vma->vm_page_prot);} EXPORT_SYMBOL(dma_mmap_coherent);
Thomas - you're the IP28 specialist. Would the plat_device_is_coherent() above have to become a cpu_is_noncoherent_r10000() call? Any further nasties?
Thanks for checking!
You're welcome!
So basically I'd not mind putting this into the Linux/MIPS tree; we still can iron out the kinks from there on and probably much better than by having arch stuff in the ALSA tree.
I recall this new API having been posted for discussion to linux-arch. What was the outcome? I'd only like to add a new API if the other arch maintainers see it fit their needs also.
Ralf
At Wed, 18 Nov 2009 15:20:56 +0100, Ralf Baechle wrote:
On Tue, Nov 17, 2009 at 10:29:10AM +0100, Takashi Iwai wrote:
Actually, this has been a looong-standing problem. I have a series of patches to fix these issues, but it's more intensively involved with dma_*() functions.
The patches can be found in test/dma-fix branch of sound GIT tree. git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git test/dma-fix
This basically adds dma_mmap_coherent() function to feasible architectures, which is already implemented for ARM, so far.
Cool - but needs a little further tweaking to work right. That's a solution which will use uncached accesses on all MIPS systems.
IP27/IP35-family machines will explode when you try that. Eventually the cache coherency logic will notice that cache, directory caches and memory have become inconsistent and bombard the CPU with a bunch of nasty exceptions.
OK, that's really bad.
Hardware designers do such things to you. Often even for a reason.
Heh, not only software engineers are so crazy ;)
For cache-coherent machines otoh it's a big waste of performance.
int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, dma_addr_t handle, size_t size) { struct page *pg;
if (!plat_device_is_coherent(dev)) vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); cpu_addr = (void *)dma_addr_to_virt(handle); pg = virt_to_page(cpu_addr);
return remap_pfn_range(vma, vma->vm_start, page_to_pfn(pg) + vma->vm_pgoff, size, vma->vm_page_prot);} EXPORT_SYMBOL(dma_mmap_coherent);
Thomas - you're the IP28 specialist. Would the plat_device_is_coherent() above have to become a cpu_is_noncoherent_r10000() call? Any further nasties?
Thanks for checking!
You're welcome!
So basically I'd not mind putting this into the Linux/MIPS tree; we still can iron out the kinks from there on and probably much better than by having arch stuff in the ALSA tree.
Yes, that's the very purpose of my patchset.
I recall this new API having been posted for discussion to linux-arch. What was the outcome? I'd only like to add a new API if the other arch maintainers see it fit their needs also.
Well, we haven't reached the consensus. The discussion faded away somehow mainly because I had too little time to update and ping people again.
In Tokyo, I talked with some guys regarding this. Ben agreed to take this approach for ppc, and David said that he doesn't mind for sparc part. Fujita-san mentioned it's no big problem to add one op from the generic dma_ops.
So, maybe somehow need to convince James in the end (and ask Paul to check SH part, too), then it'll be all up... theoretically :)
Anyway, I'm going to raise the discussion again on linux-arch. I'm afraid it's a bit too late game for 2.6.33, but starting now is better than too late again.
thanks,
Takashi
On Wed, 2009-11-18 at 18:47 +0100, Takashi Iwai wrote: [...]
Well, we haven't reached the consensus. The discussion faded away somehow mainly because I had too little time to update and ping people again.
In Tokyo, I talked with some guys regarding this. Ben agreed to take this approach for ppc, and David said that he doesn't mind for sparc part. Fujita-san mentioned it's no big problem to add one op from the generic dma_ops.
So, maybe somehow need to convince James in the end (and ask Paul to check SH part, too), then it'll be all up... theoretically :)
Anyway, I'm going to raise the discussion again on linux-arch. I'm afraid it's a bit too late game for 2.6.33, but starting now is better than too late again.
Hi, Takashi Iwai
Before the API stuff going into the mainline(2.6.33), can we apply this "[PATCH] MIPS: Fixups of ALSA memory maps"(This is the minimal necessares) as a current fixup. and then we will not get a broken sound support for MIPS, and also the support to the latest Loongson2F family machines will benefit from it.
and Ralf, what about your suggestion?
Thanks & Best wishes, Wu Zhangjin
At Sat, 21 Nov 2009 20:31:41 +0800, Wu Zhangjin wrote:
On Wed, 2009-11-18 at 18:47 +0100, Takashi Iwai wrote: [...]
Well, we haven't reached the consensus. The discussion faded away somehow mainly because I had too little time to update and ping people again.
In Tokyo, I talked with some guys regarding this. Ben agreed to take this approach for ppc, and David said that he doesn't mind for sparc part. Fujita-san mentioned it's no big problem to add one op from the generic dma_ops.
So, maybe somehow need to convince James in the end (and ask Paul to check SH part, too), then it'll be all up... theoretically :)
Anyway, I'm going to raise the discussion again on linux-arch. I'm afraid it's a bit too late game for 2.6.33, but starting now is better than too late again.
Hi, Takashi Iwai
Before the API stuff going into the mainline(2.6.33), can we apply this "[PATCH] MIPS: Fixups of ALSA memory maps"(This is the minimal necessares) as a current fixup. and then we will not get a broken sound support for MIPS, and also the support to the latest Loongson2F family machines will benefit from it.
and Ralf, what about your suggestion?
The question is whether this hack can be safely added for all MIPS platforms just by checking kconfig. I had an impression that rather many things have to be checked in the runtime.
As I have really little clue about MIPS architecture, I'd like let MIPS guys decide about it...
thanks,
Takashi
On Mon, Nov 23, 2009 at 09:56:39AM +0100, Takashi Iwai wrote:
On Wed, 2009-11-18 at 18:47 +0100, Takashi Iwai wrote: [...]
Well, we haven't reached the consensus. The discussion faded away somehow mainly because I had too little time to update and ping people again.
In Tokyo, I talked with some guys regarding this. Ben agreed to take this approach for ppc, and David said that he doesn't mind for sparc part. Fujita-san mentioned it's no big problem to add one op from the generic dma_ops.
So, maybe somehow need to convince James in the end (and ask Paul to check SH part, too), then it'll be all up... theoretically :)
Anyway, I'm going to raise the discussion again on linux-arch. I'm afraid it's a bit too late game for 2.6.33, but starting now is better than too late again.
Hi, Takashi Iwai
Before the API stuff going into the mainline(2.6.33), can we apply this "[PATCH] MIPS: Fixups of ALSA memory maps"(This is the minimal necessares) as a current fixup. and then we will not get a broken sound support for MIPS, and also the support to the latest Loongson2F family machines will benefit from it.
and Ralf, what about your suggestion?
The question is whether this hack can be safely added for all MIPS platforms just by checking kconfig. I had an impression that rather many things have to be checked in the runtime.
As I have really little clue about MIPS architecture, I'd like let MIPS guys decide about it...
Okay, I'll cook up a nice kludge. It can't cover all cases but it will be an improvment for most platforms.
Ralf
At Mon, 23 Nov 2009 12:36:15 +0000, Ralf Baechle wrote:
On Mon, Nov 23, 2009 at 09:56:39AM +0100, Takashi Iwai wrote:
On Wed, 2009-11-18 at 18:47 +0100, Takashi Iwai wrote: [...]
Well, we haven't reached the consensus. The discussion faded away somehow mainly because I had too little time to update and ping people again.
In Tokyo, I talked with some guys regarding this. Ben agreed to take this approach for ppc, and David said that he doesn't mind for sparc part. Fujita-san mentioned it's no big problem to add one op from the generic dma_ops.
So, maybe somehow need to convince James in the end (and ask Paul to check SH part, too), then it'll be all up... theoretically :)
Anyway, I'm going to raise the discussion again on linux-arch. I'm afraid it's a bit too late game for 2.6.33, but starting now is better than too late again.
Hi, Takashi Iwai
Before the API stuff going into the mainline(2.6.33), can we apply this "[PATCH] MIPS: Fixups of ALSA memory maps"(This is the minimal necessares) as a current fixup. and then we will not get a broken sound support for MIPS, and also the support to the latest Loongson2F family machines will benefit from it.
and Ralf, what about your suggestion?
The question is whether this hack can be safely added for all MIPS platforms just by checking kconfig. I had an impression that rather many things have to be checked in the runtime.
As I have really little clue about MIPS architecture, I'd like let MIPS guys decide about it...
Okay, I'll cook up a nice kludge. It can't cover all cases but it will be an improvment for most platforms.
OK, but I found that the original patch doesn't work correctly for some cases, as I mentioned in another thread. I'm going to send a patch set soon as a new thread.
thanks,
Takashi
participants (3)
-
Ralf Baechle -
Takashi Iwai -
Wu Zhangjin