Re: [Intel-gfx] Interrupt latency on some 945GM platforms -- and TCP/IP silent data corruption?

[Paolo Ornati <ornati@gmail.com>]

On Sat, 25 Sep 2010 12:28:20 +0200
Paolo Ornati <ornati@gmail.com> wrote:

> UPDATE: "processor.max_cstate=2" doesn't solve the sporadic flicker
> problem.
> 
> The patch, applied on top of 2.6.35.4, freezes the laptop on boot.
> 
> Summary:
> 	nohz=off		good
> 	processor.max_cstate=1	good
> 	processor.max_cstate=2	bad

Maybe it's not related but who knows...

on this laptop (Asus x5dij / Core(TM)2 Duo CPU T6570) I've another
problem: sporadic silent data corruption over TCP/IP!

The problem is not easy to reproduce, maybe it's something like this?
	http://www.zdnet.com/blog/ou/realtek-silent-data-corruption-caused-by-firmware/663

I've first noticed it in two ways:
	- I download an ISO and sometimes it has wrong MD5, looking
	closer I find that only a few bytes (in one place) are wrong
	- ssh detects HMAC corruption

When I've tried to reproduce it doing a lot of automated fast tranfers
over a gigabit LAN it all worked fine... ;)

The intersesting thing is that "processor.max_cstate=1" seems to have
cured this problem too!

Network controller is this:

03:00.0 Ethernet controller: Atheros Communications Atheros AR8121/AR8113/AR8114 PCI-E Ethernet Controller (rev b0)

Full lspci:
00:00.0 Host bridge: Intel Corporation Mobile 4 Series Chipset Memory Controller Hub (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 09)
00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 09)
00:1a.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 (rev 03)
00:1a.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 (rev 03)
00:1a.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 (rev 03)
00:1a.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 (rev 03)
00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03)
00:1c.0 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 1 (rev 03)
00:1c.1 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 2 (rev 03)
00:1c.5 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 6 (rev 03)
00:1d.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 (rev 03)
00:1d.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 (rev 03)
00:1d.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 (rev 03)
00:1d.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 (rev 03)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 93)
00:1f.0 ISA bridge: Intel Corporation ICH9M LPC Interface Controller (rev 03)
00:1f.2 SATA controller: Intel Corporation ICH9M/M-E SATA AHCI Controller (rev 03)
02:00.0 Network controller: Atheros Communications Inc. AR9285 Wireless Network Adapter (PCI-Express) (rev 01)
03:00.0 Ethernet controller: Atheros Communications Atheros AR8121/AR8113/AR8114 PCI-E Ethernet Controller (rev b0)

-- 
	Paolo Ornati
	Linux 2.6.35.7 on x86_64