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Commit ae1e5355 authored by Stefan Richter's avatar Stefan Richter
Browse files

firewire: deadline for PHY config transmission 

If the low-level driver failed to initialize a card properly without
noticing it, fw-core was blocked indefinitely when trying to send a
PHY config packet.  This hung up the events kernel thread, e.g. locked
up keyboard input.
https://bugzilla.redhat.com/show_bug.cgi?id=444694
https://bugzilla.redhat.com/show_bug.cgi?id=446763



This problem was introduced between 2.6.25 and 2.6.26-rc1 by commit
2a0a2590 "firewire: wait until PHY
configuration packet was transmitted (fix bus reset loop)".

The solution is to wait with timeout.  I tested it with 7 different
working controllers and 1 non-working controller.  On the working ones,
the packet callback complete()s usually --- but not always --- before a
timeout of 10ms.  Hence I chose a safer timeout of 100ms.

On the few tests with the non-working controller ALi M5271, PHY config
packet transmission always timed out so far.  (Fw-ohci needs to be fixed
for this controller independently of this deadline fix.  Often the core
doesn't even attempt to send a phy config because not even self ID
reception works.)

Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent 161b96e7

drivers/firewire/fw-transaction.c

+34 −15
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 


#include <linux/completion.h>

#include <linux/kernel.h>

#include <linux/kref.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/interrupt.h>
@@ -297,37 +298,55 @@ EXPORT_SYMBOL(fw_send_request); 
struct fw_phy_packet {

	struct fw_packet packet;

	struct completion done;

	struct kref kref;

};



static void

transmit_phy_packet_callback(struct fw_packet *packet,

static void phy_packet_release(struct kref *kref)

{

	struct fw_phy_packet *p =

			container_of(kref, struct fw_phy_packet, kref);

	kfree(p);

}



static void transmit_phy_packet_callback(struct fw_packet *packet,

					 struct fw_card *card, int status)

{

	struct fw_phy_packet *p =

			container_of(packet, struct fw_phy_packet, packet);



	complete(&p->done);

	kref_put(&p->kref, phy_packet_release);

}



void fw_send_phy_config(struct fw_card *card,

			int node_id, int generation, int gap_count)

{

	struct fw_phy_packet p;

	struct fw_phy_packet *p;

	long timeout = DIV_ROUND_UP(HZ, 10);

	u32 data = PHY_IDENTIFIER(PHY_PACKET_CONFIG) |

		   PHY_CONFIG_ROOT_ID(node_id) |

		   PHY_CONFIG_GAP_COUNT(gap_count);



	p.packet.header[0] = data;

	p.packet.header[1] = ~data;

	p.packet.header_length = 8;

	p.packet.payload_length = 0;

	p.packet.speed = SCODE_100;

	p.packet.generation = generation;

	p.packet.callback = transmit_phy_packet_callback;

	init_completion(&p.done);



	card->driver->send_request(card, &p.packet);

	wait_for_completion(&p.done);

	p = kmalloc(sizeof(*p), GFP_KERNEL);

	if (p == NULL)

		return;



	p->packet.header[0] = data;

	p->packet.header[1] = ~data;

	p->packet.header_length = 8;

	p->packet.payload_length = 0;

	p->packet.speed = SCODE_100;

	p->packet.generation = generation;

	p->packet.callback = transmit_phy_packet_callback;

	init_completion(&p->done);

	kref_set(&p->kref, 2);



	card->driver->send_request(card, &p->packet);

	timeout = wait_for_completion_timeout(&p->done, timeout);

	kref_put(&p->kref, phy_packet_release);



	/* will leak p if the callback is never executed */

	WARN_ON(timeout == 0);

}



void fw_flush_transactions(struct fw_card *card)