Bug 9120

Summary:	sysfs latency_timer for FT232RL chip
Product:	Drivers	Reporter:	Rui Guerreiro (rmg)
Component:	USB	Assignee:	Alan (alan)
Status:	RESOLVED CODE_FIX
Severity:	normal
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.22.9	Subsystem:
Regression:	No	Bisected commit-id:

Description Rui Guerreiro 2007-10-03 12:13:32 UTC

Most recent kernel where this bug did not occur: 2.6.18.1, maybe later versions (could not check)
Distribution: All
Hardware Environment: FTDI FT232RL based dongle for serial communication
Software Environment:
Problem Description:
The driver does not create the sysfs' latency_timer file for FT232RL chips (only for FT232BM and FT232C chips).
Older versions used to detect this same chip as a FT232BM compatible chip, and the latency_timer was correctly set.

Steps to reproduce:
insert a FT232RL based device on a USB plug.

Comment 1 Greg Kroah-Hartman 2007-10-03 12:54:33 UTC

This should be fixed in the 2.6.23-rc kernels, can you test there?

Comment 2 Rui Guerreiro 2007-10-04 04:16:32 UTC

Hi,
Maybe you forgot to change remove_sysfs_attrs ?

Do you see any incovenient on automagically set the latency_timer value to 2ms
(or anything around this), whenever the ASYNC_LOW_LATENCY flag is set on the
TIOCSSERIAL ioctl (set_serial_info)?
This would allow for a unified API with the "regular" UARTs, and people could
continue to use "setserial /dev/ttyUSB0 low_latency" instead of having to
fiddle around with sysfs params.