firewire: core: increase default SPLIT_TIMEOUT value (dd5eeb99) · Commits · 戴 / test

The SPLIT_TIMEOUT mechanism is intended to detect requests that somehow got lost. However, when the timeout value is too low, transactions that could have been completed successfully will be cancelled. Furthermore, there are chips whose firmwares ignore the configured split timeout and send late split response; known examples are the DM1x00 (BeBoB), TCD22x0 (DICE), and some OXUF936QSE firmwares. This patch changes the default timeout to two seconds, which happens to be the default on other OSes, too. Actual lost requests are extremely rare, so there should be no practical downside to increasing the split timeout even on devices that work correctly. Signed-off-by:

Clemens Ladisch <clemens@ladisch.de> Signed-off-by:

Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/firewire/core-card.c

+12 −4

Original line number	Diff line number	Diff line
		@@ -75,6 +75,13 @@ 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 */

		/*
		* IEEE-1394 specifies a default SPLIT_TIMEOUT value of 800 cycles (100 ms),
		* but we have to make it longer because there are many devices whose firmware
		* is just too slow for that.
		*/
		#define DEFAULT_SPLIT_TIMEOUT (2 * 8000)

		#define CANON_OUI 0x000085

		static void generate_config_rom(struct fw_card card, __be32 config_rom)
		@@ -512,10 +519,11 @@ void fw_card_initialize(struct fw_card *card,
		card->device = device;
		card->current_tlabel = 0;
		card->tlabel_mask = 0;
		card->split_timeout_hi = 0;
		card->split_timeout_lo = 800 << 19;
		card->split_timeout_cycles = 800;
		card->split_timeout_jiffies = DIV_ROUND_UP(HZ, 10);
		card->split_timeout_hi = DEFAULT_SPLIT_TIMEOUT / 8000;
		card->split_timeout_lo = (DEFAULT_SPLIT_TIMEOUT % 8000) << 19;
		card->split_timeout_cycles = DEFAULT_SPLIT_TIMEOUT;
		card->split_timeout_jiffies =
		DIV_ROUND_UP(DEFAULT_SPLIT_TIMEOUT * HZ, 8000);
		card->color = 0;
		card->broadcast_channel = BROADCAST_CHANNEL_INITIAL;

Admin message