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firewire-fixes-6.8-rc4

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This pull request includes the change to accelerate the device detection
 step in some cases.
 
 In the self-identification step after bus-reset, all of nodes in the same
 bus broadcast selfID packet including the value of gap count. The value is
 related to the cable hops between nodes, and used to calculate the
 subaction gap and the arbitration reset gap. When each node has the
 different value of the gap count, the asynchronous communication between
 them is unreliable, since an asynchronous transaction could be interrupted
 by another asynchronous transaction before completion. The gap count
 inconsistency can be resolved by several ways; e.g. the transfer of PHY
 configuration packet and generation of bus-reset.
 
 Current implementation of firewire stack can correctly detect the gap
 count inconsistency, however the recovery action from the inconsistency
 tends to be delayed after reading configuration ROM of root node. This
 results in the long time to probe devices in some combinations of
 hardware. In the pull request, the stack is changed to schedule the
 action immediately as possible.
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Merge tag 'firewire-fixes-6.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394

Pull firewire fix from Takashi Sakamoto:
 "A change to accelerate the device detection step in some cases.

  In the self-identification step after bus-reset, all nodes in the same
  bus broadcast selfID packet including the value of gap count. The
  value is related to the cable hops between nodes, and used to
  calculate the subaction gap and the arbitration reset gap.

  When each node has the different value of the gap count, the
  asynchronous communication between them is unreliable, since an
  asynchronous transaction could be interrupted by another asynchronous
  transaction before completion. The gap count inconsistency can be
  resolved by several ways; e.g. the transfer of PHY configuration
  packet and generation of bus-reset.

  The current implementation of firewire stack can correctly detect the
  gap count inconsistency, however the recovery action from the
  inconsistency tends to be delayed after reading configuration ROM of
  root node. This results in the long time to probe devices in some
  combinations of hardware.

  Here the stack is changed to schedule the action as soon as possible"

* tag 'firewire-fixes-6.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394:
  firewire: core: send bus reset promptly on gap count error
This commit is contained in:
Linus Torvalds 2024-02-10 07:56:39 -08:00
commit a38ff5bbf9
1 changed files with 17 additions and 1 deletions
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18
drivers/firewire/core-card.c
View File

@ -429,7 +429,23 @@ static void bm_work(struct work_struct *work)
*/
card->bm_generation = generation;
if (root_device == NULL) {
if (card->gap_count == 0) {
/*
* If self IDs have inconsistent gap counts, do a
* bus reset ASAP. The config rom read might never
* complete, so don't wait for it. However, still
* send a PHY configuration packet prior to the
* bus reset. The PHY configuration packet might
* fail, but 1394-2008 8.4.5.2 explicitly permits
* it in this case, so it should be safe to try.
*/
new_root_id = local_id;
/*
* We must always send a bus reset if the gap count
* is inconsistent, so bypass the 5-reset limit.
*/
card->bm_retries = 0;
} else if (root_device == NULL) {
/*
* Either link_on is false, or we failed to read the
* config rom. In either case, pick another root.