From db5d247ae811f49185a71e703b65acad845e4b18 Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Thu, 24 Dec 2009 12:05:58 +0100 Subject: firewire: fix use of multiple AV/C devices, allow multiple FCP listeners Control of more than one AV/C device at once --- e.g. camcorders, tape decks, audio devices, TV tuners --- failed or worked only unreliably, depending on driver implementation. This affected kernelspace and userspace drivers alike and was caused by firewire-core's inability to accept multiple registrations of FCP listeners. The fix allows multiple address handlers to be registered for the FCP command and response registers. When a request for these registers is received, all handlers are invoked, and the Firewire response is generated by the core and not by any handler. The cdev API does not change, i.e., userspace is still expected to send a response for FCP requests; this response is silently ignored. Signed-off-by: Clemens Ladisch Signed-off-by: Stefan Richter (changelog, rebased, whitespace) --- include/linux/firewire-cdev.h | 3 +++ include/linux/firewire.h | 4 ++-- 2 files changed, 5 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/firewire-cdev.h b/include/linux/firewire-cdev.h index c6b3ca3af6df..1f716d9f714b 100644 --- a/include/linux/firewire-cdev.h +++ b/include/linux/firewire-cdev.h @@ -340,6 +340,9 @@ struct fw_cdev_send_response { * The @closure field is passed back to userspace in the response event. * The @handle field is an out parameter, returning a handle to the allocated * range to be used for later deallocation of the range. + * + * The address range is allocated on all local nodes. The address allocation + * is exclusive except for the FCP command and response registers. */ struct fw_cdev_allocate { __u64 offset; diff --git a/include/linux/firewire.h b/include/linux/firewire.h index 9416a461b696..a0e67150a729 100644 --- a/include/linux/firewire.h +++ b/include/linux/firewire.h @@ -248,8 +248,8 @@ typedef void (*fw_transaction_callback_t)(struct fw_card *card, int rcode, void *data, size_t length, void *callback_data); /* - * Important note: The callback must guarantee that either fw_send_response() - * or kfree() is called on the @request. + * Important note: Except for the FCP registers, the callback must guarantee + * that either fw_send_response() or kfree() is called on the @request. */ typedef void (*fw_address_callback_t)(struct fw_card *card, struct fw_request *request, -- cgit v1.2.3