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Commit 0555cb98 authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
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staging/fwserial: Limit tx/rx to 1394-2008 spec maximum 

Per this conversation https://lkml.org/lkml/2012/11/27/587


limit the maximum transmission to the IEEE 1394-2008 specification
maximum size of 4096 bytes for asynchronous packets.

Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Acked-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 99293623

drivers/staging/fwserial/TODO

+0 −3
Original line number Diff line number Diff line
@@ -12,9 +12,6 @@ TODOs 
1. This driver uses the same unregistered vendor id that the firewire core does

     (0xd00d1e). Perhaps this could be exposed as a define in

     firewire-constants.h?

2. MAX_ASYNC_PAYLOAD needs to be publicly exposed by core/ohci

   - otherwise how will this driver know the max size of address window to

     open for one packet write?

3. Maybe device_max_receive() and link_speed_to_max_payload() should be

     taken up by the firewire core?

4. To avoid dropping rx data while still limiting the maximum buffering,

drivers/staging/fwserial/fwserial.c

+1 −1
Original line number Diff line number Diff line
@@ -179,7 +179,7 @@ static void dump_profile(struct seq_file *m, struct stats *stats) 
/* Returns the max receive packet size for the given card */

static inline int device_max_receive(struct fw_device *fw_device)

{

	return 1 <<  (clamp_t(int, fw_device->max_rec, 8U, 13U) + 1);

	return 1 <<  (clamp_t(int, fw_device->max_rec, 8U, 11U) + 1);

}



static void fwtty_log_tx_error(struct fwtty_port *port, int rcode)

drivers/staging/fwserial/fwserial.h

+3 −3
Original line number Diff line number Diff line
@@ -374,10 +374,10 @@ static inline void fwtty_bind_console(struct fwtty_port *port, 
 */

static inline int link_speed_to_max_payload(unsigned speed)

{

	static const int max_async[] = { 307, 614, 1229, 2458, 4916, 9832, };

	BUILD_BUG_ON(ARRAY_SIZE(max_async) - 1 != SCODE_3200);

	static const int max_async[] = { 307, 614, 1229, 2458, };

	BUILD_BUG_ON(ARRAY_SIZE(max_async) - 1 != SCODE_800);



	speed = clamp(speed, (unsigned) SCODE_100, (unsigned) SCODE_3200);

	speed = clamp(speed, (unsigned) SCODE_100, (unsigned) SCODE_800);

	if (limit_bw)

		return max_async[speed];

	else