From 6044565af458e7fa6e748bff437ecc49dea88d79 Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Sat, 15 Jan 2011 18:19:48 +0100 Subject: [PATCH] firewire: core: fix unstable I/O with Canon camcorder Regression since commit 10389536742c, "firewire: core: check for 1394a compliant IRM, fix inaccessibility of Sony camcorder": The camcorder Canon MV5i generates lots of bus resets when asynchronous requests are sent to it (e.g. Config ROM read requests or FCP Command write requests) if the camcorder is not root node. This causes drop- outs in videos or makes the camcorder entirely inaccessible. https://bugzilla.redhat.com/show_bug.cgi?id=633260 Fix this by allowing any Canon device, even if it is a pre-1394a IRM like MV5i are, to remain root node (if it is at least Cycle Master capable). With the FireWire controller cards that I tested, MV5i always becomes root node when plugged in and left to its own devices. Reported-by: Ralf Lange Signed-off-by: Stefan Richter Cc: # 2.6.32.y and newer --- drivers/firewire/core-card.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c index be0492398ef9..24ff35511e2b 100644 --- a/drivers/firewire/core-card.c +++ b/drivers/firewire/core-card.c @@ -75,6 +75,8 @@ static size_t config_rom_length = 1 + 4 + 1 + 1; #define BIB_IRMC ((1) << 31) #define NODE_CAPABILITIES 0x0c0083c0 /* per IEEE 1394 clause 8.3.2.6.5.2 */ +#define CANON_OUI 0x000085 + static void generate_config_rom(struct fw_card *card, __be32 *config_rom) { struct fw_descriptor *desc; @@ -284,6 +286,7 @@ static void bm_work(struct work_struct *work) bool root_device_is_running; bool root_device_is_cmc; bool irm_is_1394_1995_only; + bool keep_this_irm; spin_lock_irq(&card->lock); @@ -305,6 +308,10 @@ static void bm_work(struct work_struct *work) irm_is_1394_1995_only = irm_device && irm_device->config_rom && (irm_device->config_rom[2] & 0x000000f0) == 0; + /* Canon MV5i works unreliably if it is not root node. */ + keep_this_irm = irm_device && irm_device->config_rom && + irm_device->config_rom[3] >> 8 == CANON_OUI; + root_id = root_node->node_id; irm_id = card->irm_node->node_id; local_id = card->local_node->node_id; @@ -333,7 +340,7 @@ static void bm_work(struct work_struct *work) goto pick_me; } - if (irm_is_1394_1995_only) { + if (irm_is_1394_1995_only && !keep_this_irm) { new_root_id = local_id; fw_notify("%s, making local node (%02x) root.\n", "IRM is not 1394a compliant", new_root_id); @@ -382,7 +389,7 @@ static void bm_work(struct work_struct *work) spin_lock_irq(&card->lock); - if (rcode != RCODE_COMPLETE) { + if (rcode != RCODE_COMPLETE && !keep_this_irm) { /* * The lock request failed, maybe the IRM * isn't really IRM capable after all. Let's