linux/drivers/firewire
Takashi Sakamoto d0b06dc48f firewire: core: use long bus reset on gap count error
When resetting the bus after a gap count error, use a long rather than
short bus reset.

IEEE 1394-1995 uses only long bus resets. IEEE 1394a adds the option of
short bus resets. When video or audio transmission is in progress and a
device is hot-plugged elsewhere on the bus, the resulting bus reset can
cause video frame drops or audio dropouts. Short bus resets reduce or
eliminate this problem. Accordingly, short bus resets are almost always
preferred.

However, on a mixed 1394/1394a bus, a short bus reset can trigger an
immediate additional bus reset. This double bus reset can be interpreted
differently by different nodes on the bus, resulting in an inconsistent gap
count after the bus reset. An inconsistent gap count will cause another bus
reset, leading to a neverending bus reset loop. This only happens for some
bus topologies, not for all mixed 1394/1394a buses.

By instead sending a long bus reset after a gap count inconsistency, we
avoid the doubled bus reset, restoring the bus to normal operation.

Signed-off-by: Adam Goldman <adamg@pobox.com>
Link: https://sourceforge.net/p/linux1394/mailman/message/58741624/
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
2024-02-29 22:18:14 +09:00
..
.kunitconfig firewire: test: add KUnit test for device attributes 2024-01-08 09:36:56 +09:00
core-card.c firewire: core: use long bus reset on gap count error 2024-02-29 22:18:14 +09:00
core-cdev.c firewire: cdev: implement new event relevant to phy packet with time stamp 2023-05-30 08:12:40 +09:00
core-device.c firewire: core: search descriptor leaf just after vendor directory entry in root directory 2024-02-01 20:53:18 +09:00
core-iso.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
core-topology.c Revert "firewire: core: obsolete usage of GFP_ATOMIC at building node tree" 2023-09-15 18:37:52 +09:00
core-transaction.c firewire: core: implement variations to send request and wait for response with time stamp 2023-05-30 08:12:40 +09:00
core.h firewire: Annotate struct fw_node with __counted_by 2023-11-05 21:15:17 +09:00
device-attribute-test.c firewire: core: fill model field in modalias of unit device for legacy layout of configuration ROM 2024-01-10 18:37:13 +09:00
init_ohci1394_dma.c firewire: init_ohci1394_dma: use correct function names in comments 2023-04-24 09:19:35 +09:00
Kconfig firewire: test: add KUnit test for device attributes 2024-01-08 09:36:56 +09:00
Makefile firewire: add KUnit test to check layout of UAPI structures 2023-05-30 08:12:39 +09:00
net.c firewire: net: fix use after free in fwnet_finish_incoming_packet() 2023-06-24 14:03:46 +09:00
nosy-user.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
nosy.c firewire: nosy: switch from 'pci_' to 'dma_' API 2021-07-05 22:23:15 +02:00
nosy.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ohci.c firewire: ohci: suppress unexpected system reboot in AMD Ryzen machines and ASM108x/VT630x PCIe cards 2024-01-05 21:28:08 +09:00
ohci.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sbp2.c scsi: Change SCSI device boolean fields to single bit flags 2023-11-24 20:44:21 -05:00
uapi-test.c firewire: fix build failure due to missing module license 2023-05-30 19:37:29 +09:00