On Fri, 28 Jun 2019 09:34:00 +0200, Takashi Sakamoto wrote:
Hi,
On Fri, Jun 28, 2019, at 17:53, Takashi Iwai wrote:
On Fri, 28 Jun 2019 07:21:58 +0200, Takashi Sakamoto wrote:
In IEC 61883-6, 8 MIDI data streams are multiplexed into single MIDI conformant data channel. The index of stream is calculated by modulo 8 of the value of data block counter.
In fireworks, the value of data block counter in CIP header has a quirk with firmware version v5.0.0, v5.7.3 and v5.8.0. This brings ALSA IEC 61883-1/6 packet streaming engine to miss detection of MIDI messages.
This commit fixes the miss detection to modify the value of data block counter for the modulo calculation.
For maintainers, this bug exists since a commit 18f5ed365d3f ("ALSA: fireworks/firewire-lib: add support for recent firmware quirk") in Linux kernel v4.2. There're many changes since the commit. This fix can be backported to Linux kernel v4.4 or later. I tagged a base commit to the backport for your convenience.
Fixes: df075feefbd3 ("ALSA: firewire-lib: complete AM824 data block processing layer") Cc: stable@vger.kernel.org # v4.4+ Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp
This doesn't seem applicable to the latest 5.2-rc tree due to your recent refactoring. Could you resubmit the fix for 5.2? I'll resolve the merge conflict in my side.
Mmm. Do you actually encounter any conflict when applying this patch to your v5.2 tree?
This patch includes changes for `sound/firewire/amdtp-am824.c`. On the other hand, my recent work is mainly for `sound/firewire/amdtp-stream.c`. Actually, the last change for `amdtp-am824.c` was done 2017-10-25. https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git/log/sound/fi...
It's not about file conflicts but the compilation fails after the patch. sound/firewire/amdtp-am824.c: In function ‘read_midi_messages’: sound/firewire/amdtp-am824.c:324:16: error: ‘struct amdtp_stream’ has no member named ‘ctx_data’ port = (8 - s->ctx_data.tx.first_dbc + s->data_block_counter + f) % 8; ^~
thanks,
Takashi