Hello,
After upgrading to 2.6.32 I experienced strange behavior with a
usb-serial device. I have an application running to capture 433Mhz RF
transmissions using RF-receiver (from rfxcom.com) which has an built-in
serial-2-usb ftdi chip, connected to an older Dell laptop. After
programming the RF receive mode on startup of application, the device
will be sending messages (few bytes) whenever it receives some valid RF
data, nothing is transmitted anymore from the PC side.
This has been running fine without problems for over a year,
occasionally upgrading to latest kernel, that's until I upgraded from
2.6.31 to 2.6.32.
I'm seeing that serial data seems to get buffered somehow, nothing is
received on the laptop for tens of minutes, even stranger is that moving
the (usb-)mouse seems to trigger something and all the "buffered" serial
data is suddenly received in a burst.
Problem gets worse when there are other activities going on and less
notable when the laptop is more or less idle.
I would attempt a kernel bi-sect but that would take days to trigger as
problem manifest itself usually only some time after booting or
restarting application. I did suspect maybe the serial driver itself,
so I copied the 2.6.31 version of the ftdi_sio.c|h files into 2.6.32
source but that didn't make any difference.
I'm now back on 2.6.31.9 and all is fine, any ideas/clues on where to look ?
Thanks,
Ruud
==
# lsusb
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 007: ID 04b4:fd13 Cypress Semiconductor Corp.
Bus 001 Device 008: ID 046d:c001 Logitech, Inc. N48/M-BB48 [FirstMouse Plus]
Bus 001 Device 004: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial
Port
Bus 001 Device 005: ID 0403:6001 Future Technology Devices
International, Ltd FT232 USB-Serial (UART) IC
Bus 001 Device 006: ID 04fc:05d8 Sunplus Technology Co., Ltd
Bus 001 Device 003: ID 058f:9254 Alcor Micro Corp. Hub
Bus 001 Device 002: ID 413c:0058 Dell Computer Corp. Port Replicator
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
# cat /proc/interrupts
CPU0
0: 17497286 XT-PIC-XT timer
1: 424 XT-PIC-XT i8042
2: 0 XT-PIC-XT cascade
3: 299463 XT-PIC-XT pata_pcmcia
4: 17570 XT-PIC-XT serial
5: 0 XT-PIC-XT Intel 82801DB-ICH4
7: 2 XT-PIC-XT parport0
8: 25 XT-PIC-XT rtc0
9: 2 XT-PIC-XT acpi
10: 2 XT-PIC-XT
11: 107604090 XT-PIC-XT yenta, yenta, ehci_hcd:usb1,
uhci_hcd:usb2, uhci_hcd:usb3, uhci_hcd:usb4, eth0, radeon@pci:0000:01:00.0
12: 169 XT-PIC-XT i8042
14: 49953 XT-PIC-XT ata_piix
15: 58 XT-PIC-XT ata_piix
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