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A maintainer of Linux FireWire subsystem and ALSA firewire stack.
http://ieee1394.docs.kernel.org/
https://github.com/takaswie/linux-firewire-dkms/

Takashi Sakamoto (坂本 貴史)

I posted:

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Takashi Sakamoto (坂本 貴史)

Hm:

An end to high memory?
https://lwn.net/Articles/813201/
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Takashi Sakamoto (坂本 貴史)

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Takashi Sakamoto (坂本 貴史)

I just tried, for now:
[PATCH] scatterlist: remove ambiguous comment for public fields count of mapping iterator
https://lore.kernel.org/lkml/20251214032533.702368-1-o-takashi@sakamocchi.jp/T/#u
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Takashi Sakamoto (坂本 貴史)

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Takashi Sakamoto (坂本 貴史)

A new user appeared for a pair of dma_alloc_pages() and dma_free_pages()...

[PATCH v12 6/9] tee: add tee_shm_alloc_dma_mem()
https://lore.kernel.org/op-tee/20250911135007.1275833-7-jens.wiklander@linaro.org/
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Takashi Sakamoto (坂本 貴史)

I'm trying using the following utilities to eliminate the usage of page_private() from 1394 OHCI and core:

* struct scatterlist
* struct sg_table
* dma_alloc_noncontiguous()
* dma_vmap_noncontiguous()
* dma_mmap_noncontiguous()

I've never tested yet the integration.
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Takashi Sakamoto (坂本 貴史)

when we can assume either PartialEq or Eq.
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Takashi Sakamoto (坂本 貴史)

ptr_0 == ptr_1

equals to

ptr_0->node_id == ptr_1->node_id &&
ptr_0->tlabel == ptr_1->tlabel

but

ptr_0->node_id == ptr_1->node_id &&
ptr_0->tlabel == ptr_1->tlabel

does not equals to

ptr_0 == ptr_1
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Takashi Sakamoto (坂本 貴史)

Edited 3 months ago
acknowledge code = 0x10 to any type of transaction is out of specification. MOTU Audio Express.
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Takashi Sakamoto (坂本 貴史)

I sent:

[GIT PULL] firewire updates for v6.18 kernel
https://lore.kernel.org/lkml/20250929134642.GA748211@workstation.local/

That was some tough code refactoring, but continued...
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Takashi Sakamoto (坂本 貴史)

[linux-next:master 11811/12740] drivers/firewire/core-transaction.c:1255: undefined reference to `__aeabi_uldivmod'
https://lore.kernel.org/oe-kbuild-all/202509270428.FZaO2PPq-lkp@intel.com/

Oh...
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Takashi Sakamoto (坂本 貴史)

Ah, indeed. IntMask, synchronize_irq(), then losing contender and bus reset.
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Takashi Sakamoto (坂本 貴史)

Edited 3 months ago
At depth-first search, update of color value at first works well to detect parent node in the list of port, as long as the color value of fw_node is different from the one of fw_card. However, we have no guarantee...
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Takashi Sakamoto (坂本 貴史)

Hm. The way to use local stack is a bit peaky...
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Takashi Sakamoto (坂本 貴史)

The error path from "build_tree" in "drivers/firewire/core-topology.c" causes memory leak since it's initial commit:

https://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394.git/tree/drivers/firewire/core-topology.c?id=07e27ad16399afcd693be20211b0dfae63e0615f#n98

I guess that it relies on the correctness of Self ID sequence retrieved by Self ID receive DMA context in 1394 OHCI specification. Hm.
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Takashi Sakamoto (坂本 貴史)

Even if in the case of KUnit tests, it should be better to follow the listriction of kernel stack usage...

```
../drivers/firewire/topology-helper-test.c:184:1: warning: the frame size of 1636 bytes is larger than 1024 bytes [-Wframe-larger-than=]
184 | }
| ^
```
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