[ Upstream commit d0b06dc48fb15902d7da09c5c0861e7f042a9381 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 7ed4380009e96d9e9c605e12822e987b35b05648 ]
If we are bus manager and the bus has inconsistent gap counts, send a
bus reset immediately instead of trying to read the root node's config
ROM first. Otherwise, we could spend a lot of time trying to read the
config ROM but never succeeding.
This eliminates a 50+ second delay before the FireWire bus is usable after
a newly connected device is powered on in certain circumstances.
The delay occurs if a gap count inconsistency occurs, we are not the root
node, and we become bus manager. One scenario that causes this is with a TI
XIO2213B OHCI, the first time a Sony DSR-25 is powered on after being
connected to the FireWire cable. In this configuration, the Linux box will
not receive the initial PHY configuration packet sent by the DSR-25 as IRM,
resulting in the DSR-25 having a gap count of 44 while the Linux box has a
gap count of 63.
FireWire devices have a gap count parameter, which is set to 63 on power-up
and can be changed with a PHY configuration packet. This determines the
duration of the subaction and arbitration gaps. For reliable communication,
all nodes on a FireWire bus must have the same gap count.
A node may have zero or more of the following roles: root node, bus manager
(BM), isochronous resource manager (IRM), and cycle master. Unless a root
node was forced with a PHY configuration packet, any node might become root
node after a bus reset. Only the root node can become cycle master. If the
root node is not cycle master capable, the BM or IRM should force a change
of root node.
After a bus reset, each node sends a self-ID packet, which contains its
current gap count. A single bus reset does not change the gap count, but
two bus resets in a row will set the gap count to 63. Because a consistent
gap count is required for reliable communication, IEEE 1394a-2000 requires
that the bus manager generate a bus reset if it detects that the gap count
is inconsistent.
When the gap count is inconsistent, build_tree() will notice this after the
self identification process. It will set card->gap_count to the invalid
value 0. If we become bus master, this will force bm_work() to send a bus
reset when it performs gap count optimization.
After a bus reset, there is no bus manager. We will almost always try to
become bus manager. Once we become bus manager, we will first determine
whether the root node is cycle master capable. Then, we will determine if
the gap count should be changed. If either the root node or the gap count
should be changed, we will generate a bus reset.
To determine if the root node is cycle master capable, we read its
configuration ROM. bm_work() will wait until we have finished trying to
read the configuration ROM.
However, an inconsistent gap count can make this take a long time.
read_config_rom() will read the first few quadlets from the config ROM. Due
to the gap count inconsistency, eventually one of the reads will time out.
When read_config_rom() fails, fw_device_init() calls it again until
MAX_RETRIES is reached. This takes 50+ seconds.
Once we give up trying to read the configuration ROM, bm_work() will wake
up, assume that the root node is not cycle master capable, and do a bus
reset. Hopefully, this will resolve the gap count inconsistency.
This change makes bm_work() check for an inconsistent gap count before
waiting for the root node's configuration ROM. If the gap count is
inconsistent, bm_work() will immediately do a bus reset. This eliminates
the 50+ second delay and rapidly brings the bus to a working state.
I considered that if the gap count is inconsistent, a PHY configuration
packet might not be successful, so it could be desirable to skip the PHY
configuration packet before the bus reset in this case. However, IEEE
1394a-2000 and IEEE 1394-2008 say that the bus manager may transmit a PHY
configuration packet before a bus reset when correcting a gap count error.
Since the standard endorses this, I decided it's safe to retain the PHY
configuration packet transmission.
Normally, after a topology change, we will reset the bus a maximum of 5
times to change the root node and perform gap count optimization. However,
if there is a gap count inconsistency, we must always generate a bus reset.
Otherwise the gap count inconsistency will persist and communication will
be unreliable. For that reason, if there is a gap count inconstency, we
generate a bus reset even if we already reached the 5 reset limit.
Signed-off-by: Adam Goldman <adamg@pobox.com>
Reference: https://sourceforge.net/p/linux1394/mailman/message/58727806/
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 5f9ab17394f831cb7986ec50900fa37507a127f1 upstream.
Against its current description, the kernel API can accepts all types of
directory entries.
This commit corrects the documentation.
Cc: stable@vger.kernel.org
Fixes: 3c2c58cb33b3 ("firewire: core: fw_csr_string addendum")
Link: https://lore.kernel.org/r/20240130100409.30128-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ac9184fbb8478dab4a0724b279f94956b69be827 upstream.
VIA VT6306/6307/6308 provides PCI interface compliant to 1394 OHCI. When
the hardware is combined with Asmedia ASM1083/1085 PCIe-to-PCI bus bridge,
it appears that accesses to its 'Isochronous Cycle Timer' register (offset
0xf0 on PCI memory space) often causes unexpected system reboot in any
type of AMD Ryzen machine (both 0x17 and 0x19 families). It does not
appears in the other type of machine (AMD pre-Ryzen machine, Intel
machine, at least), or in the other OHCI 1394 hardware (e.g. Texas
Instruments).
The issue explicitly appears at a commit dcadfd7f7c74 ("firewire: core:
use union for callback of transaction completion") added to v6.5 kernel.
It changed 1394 OHCI driver to access to the register every time to
dispatch local asynchronous transaction. However, the issue exists in
older version of kernel as long as it runs in AMD Ryzen machine, since
the access to the register is required to maintain bus time. It is not
hard to imagine that users experience the unexpected system reboot when
generating bus reset by plugging any devices in, or reading the register
by time-aware application programs; e.g. audio sample processing.
This commit suppresses the unexpected system reboot in the combination of
hardware. It avoids the access itself. As a result, the software stack can
not provide the hardware time anymore to unit drivers, userspace
applications, and nodes in the same IEEE 1394 bus. It brings apparent
disadvantage since time-aware application programs require it, while
time-unaware applications are available again; e.g. sbp2.
Cc: stable@vger.kernel.org
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Closes: https://bugzilla.suse.com/show_bug.cgi?id=1215436
Reported-by: Mario Limonciello <mario.limonciello@amd.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217994
Reported-by: Tobias Gruetzmacher <tobias-lists@23.gs>
Closes: https://sourceforge.net/p/linux1394/mailman/message/58711901/
Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2240973
Closes: https://bugs.launchpad.net/linux/+bug/2043905
Link: https://lore.kernel.org/r/20240102110150.244475-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 891e0eab32a57fca4d36c5162628eb0bcb1f0edf upstream.
If device_register() fails, the refcount of device is not 0, the name
allocated in dev_set_name() is leaked. To fix this by calling put_device(),
so that it will be freed in callback function kobject_cleanup().
unreferenced object 0xffff9d99035c7a90 (size 8):
comm "systemd-udevd", pid 168, jiffies 4294672386 (age 152.089s)
hex dump (first 8 bytes):
66 77 30 2e 30 00 ff ff fw0.0...
backtrace:
[<00000000e1d62bac>] __kmem_cache_alloc_node+0x1e9/0x360
[<00000000bbeaff31>] __kmalloc_node_track_caller+0x44/0x1a0
[<00000000491f2fb4>] kvasprintf+0x67/0xd0
[<000000005b960ddc>] kobject_set_name_vargs+0x1e/0x90
[<00000000427ac591>] dev_set_name+0x4e/0x70
[<000000003b4e447d>] create_units+0xc5/0x110
fw_unit_release() will be called in the error path, move fw_device_get()
before calling device_register() to keep balanced with fw_device_put() in
fw_unit_release().
Cc: stable@vger.kernel.org
Fixes: 1fa5ae857bb1 ("driver core: get rid of struct device's bus_id string array")
Fixes: a1f64819fe9f ("firewire: struct device - replace bus_id with dev_name(), dev_set_name()")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
