Re: [PATCH 0/4] firewire: core: handle TASCAM FW-1884/FW-1804/FW-1082 quirk
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From: Takashi S. <o-t...@sa...> - 2025-10-20 00:19:43
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On Sat, Oct 18, 2025 at 12:55:28PM +0900, Takashi Sakamoto wrote: > Hi, > > In 2003, TEAC Corporation had released FW-1884/FW-1804/FW-1082 in its > TASCAM brand. These devices are already supported by a driver in ALSA > firewire stack, but they have an interoperability issue related to > the speed of asynchronous transactions and isochronous transmissions. > When operating at the speed described in configuration ROM, they are > too lazy to respond, and eventually frozen. > > The most likely cause of this issue is a mismatch in the gap count > between the initiators and receivers. Theoretically, this can be > resolved by transmitting phy configuration packets to optimize gap count. > Nevertheless, this approach has proven ineffective, suggesting that the > device firmware may contain a bug causing the issue. > > From my experience, these devices operate more reliably at lower > transaction and transmission speeds, which provides a practical > mitigation. > > This patch series addresses the interoperability issue. The core function > of Linux FireWire subsystem is changed to read the entire configuration > ROM at the lowest speed (S100), and to identify these devices based on its > contents. Once identified, their maximum speed is limited to S200. The > ALSA driver then performs asynchronous requests and isochronous > transmission at that speed to prevent device freezes. > > Takashi Sakamoto (4): > firewire: core: code refactoring to compute transaction speed > firewire: core: determine transaction speed after detecting quirks > firewire: core: handle device quirk of TASCAM FW-1884/FW-1804/FW-1082 > ALSA: firewire-tascam: reserve resources for transferred isochronous > packets at S400 > > drivers/firewire/core-device.c | 86 +++++++++++++++------------ > include/linux/firewire.h | 3 + > sound/firewire/tascam/tascam-stream.c | 21 +++---- > 3 files changed, 63 insertions(+), 47 deletions(-) > > > base-commit: 15f9610fc96ac6fd2844e63f7bf5a0b08e1c31c8 Applied to for-next branch. To sound subsystem maintainer, I'll send the 4th patch to mainline as a part of firewire subsystem updates in next merge window. Regards Takashi Sakamoto ` |