sysfs question

sysfs question

[Mark Ryden]

Hello,
I am trying to follow the
Linux Containers - Network Namespace configuration instructions from
http://lxc.sourceforge.net/network/configuration.php


I had built a kernel with CONFIG_SYS=n and  CONFIG_NET_NS=y
and CONFIG_VETH=y , etc, according to the instructions.


Now, the CONFIG_SYSFS help text says:

sysfs is currently used by the block subsystem to mount the root
partition. If sysfs is disabled you must specify the boot device on
the kernel boot command line via its major and minor numbers. For
example, "root=03:01" for /dev/hda1.


So I added root=08,02 to my kernel boot parameter line and booted.


it starts booting, but then gets:
switchroot: mount failed: No such file or directory.
Booting has failed.

8 is the majoror number and 2 is the minor number of /dev/sda2, where I have
my root partition.

Googling for this found the following, which not helped much:
http://linux.derkeiler.com/Mailing-Lists/Kernel/2007-11/msg05032.html

Any ideas?
Regards,
Mark

Re: sysfs question

[Mark Ryden]

In fact, after looking more closely, I see that before that message appears:
Error: unmouting old /sys
ERROR unmounting old /sys: Invalid argument.
forcing unmount of /sys
switchroot...

Any ideas?
Rgs,
Mark


On Thu, Sep 11, 2008 at 5:01 PM, Mark Ryden <markryde-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> Hello,
> I am trying to follow the
> Linux Containers - Network Namespace configuration instructions from
> http://lxc.sourceforge.net/network/configuration.php
>
>
> I had built a kernel with CONFIG_SYS=n and  CONFIG_NET_NS=y
> and CONFIG_VETH=y , etc, according to the instructions.
>
>
> Now, the CONFIG_SYSFS help text says:
>
> sysfs is currently used by the block subsystem to mount the root
> partition. If sysfs is disabled you must specify the boot device on
> the kernel boot command line via its major and minor numbers. For
> example, "root=03:01" for /dev/hda1.
>
>
> So I added root=08,02 to my kernel boot parameter line and booted.
>
>
> it starts booting, but then gets:
> switchroot: mount failed: No such file or directory.
> Booting has failed.
>
> 8 is the majoror number and 2 is the minor number of /dev/sda2, where I have
> my root partition.
>
> Googling for this found the following, which not helped much:
> http://linux.derkeiler.com/Mailing-Lists/Kernel/2007-11/msg05032.html
>
> Any ideas?
> Regards,
> Mark
>

Re: sysfs question

[xiaoming.zhang]

On Thursday 11 September 2008 10:05:43 pm Mark Ryden wrote:
> In fact, after looking more closely, I see that before that message
> appears: Error: unmouting old /sys
> ERROR unmounting old /sys: Invalid argument.
> forcing unmount of /sys
> switchroot...
>

My experience is you'd better to find a sysfs patch, since the sysfs 
filesystem is required by ramdisk and some system utilities, e.g., system 
network configuration scripts.

Patch for mm-tree can be found here:
	http://lxc.sourceforge.net/patches/2.6.26/

This is what I used:
http://lxc.sourceforge.net/patches/2.6.26/2.6.26-rc8-mm1-lxc1/broken-out/sysfs/

I merged these 11 patches on Linux-2.6.26.1 though I don't understand these 
patches, luckily enough it worked for me.

> Any ideas?
> Rgs,
> Mark
>
> On Thu, Sep 11, 2008 at 5:01 PM, Mark Ryden <markryde-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > Hello,
> > I am trying to follow the
> > Linux Containers - Network Namespace configuration instructions from
> > http://lxc.sourceforge.net/network/configuration.php
> >
> >
> > I had built a kernel with CONFIG_SYS=n and  CONFIG_NET_NS=y
> > and CONFIG_VETH=y , etc, according to the instructions.
> >
> >
> > Now, the CONFIG_SYSFS help text says:
> >
> > sysfs is currently used by the block subsystem to mount the root
> > partition. If sysfs is disabled you must specify the boot device on
> > the kernel boot command line via its major and minor numbers. For
> > example, "root=03:01" for /dev/hda1.
> >
> >
> > So I added root=08,02 to my kernel boot parameter line and booted.
> >
> >
> > it starts booting, but then gets:
> > switchroot: mount failed: No such file or directory.
> > Booting has failed.
> >
> > 8 is the majoror number and 2 is the minor number of /dev/sda2, where I
> > have my root partition.
> >
> > Googling for this found the following, which not helped much:
> > http://linux.derkeiler.com/Mailing-Lists/Kernel/2007-11/msg05032.html
> >
> > Any ideas?
> > Regards,
> > Mark
>
> _______________________________________________
> Containers mailing list
> Containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
> https://lists.linux-foundation.org/mailman/listinfo/containers



-- 
Have fun,
Xiaoming Zhang

Re: sysfs question

[Daniel Lezcano]

xiaoming.zhang wrote:
> On Thursday 11 September 2008 10:05:43 pm Mark Ryden wrote:
>> In fact, after looking more closely, I see that before that message
>> appears: Error: unmouting old /sys
>> ERROR unmounting old /sys: Invalid argument.
>> forcing unmount of /sys
>> switchroot...
>>
> 
> My experience is you'd better to find a sysfs patch, since the sysfs 
> filesystem is required by ramdisk and some system utilities, e.g., system 
> network configuration scripts.
> 
> Patch for mm-tree can be found here:
> 	http://lxc.sourceforge.net/patches/2.6.26/
> 
> This is what I used:
> http://lxc.sourceforge.net/patches/2.6.26/2.6.26-rc8-mm1-lxc1/broken-out/sysfs/
> 
> I merged these 11 patches on Linux-2.6.26.1 though I don't understand these 
> patches, luckily enough it worked for me.

As mentioned Benjamin, it is hard to boot a distro without sysfs. I 
think it is a good idea to use the lxc patchset.

You can use the latest version:

http://lxc.sourceforge.net/patches/2.6.27/2.6.27-rc6-lxc1/

If you want to play with the container, you have the userspace tools at:

http://lxc.sourceforge.net/download/lxc/

Don't forget to check the README in the directory ;)

   -- Daniel

Re: sysfs question

[xiaoming.zhang]

On Thursday 11 September 2008 11:37:33 pm Daniel Lezcano wrote:
> xiaoming.zhang wrote:
> > On Thursday 11 September 2008 10:05:43 pm Mark Ryden wrote:
> >> In fact, after looking more closely, I see that before that message
> >> appears: Error: unmouting old /sys
> >> ERROR unmounting old /sys: Invalid argument.
> >> forcing unmount of /sys
> >> switchroot...
> >
> > My experience is you'd better to find a sysfs patch, since the sysfs
> > filesystem is required by ramdisk and some system utilities, e.g., system
> > network configuration scripts.
> >
> > Patch for mm-tree can be found here:
> > 	http://lxc.sourceforge.net/patches/2.6.26/
> >
> > This is what I used:
> > http://lxc.sourceforge.net/patches/2.6.26/2.6.26-rc8-mm1-lxc1/broken-out/
> >sysfs/
> >
> > I merged these 11 patches on Linux-2.6.26.1 though I don't understand
> > these patches, luckily enough it worked for me.
>
> As mentioned Benjamin, it is hard to boot a distro without sysfs. I
> think it is a good idea to use the lxc patchset.
>
> You can use the latest version:
>
> http://lxc.sourceforge.net/patches/2.6.27/2.6.27-rc6-lxc1/
>
Thank you very much. And is there any patchset for Linux-2.6.26.* (not the 
mm-tree)?


> If you want to play with the container, you have the userspace tools at:
>
> http://lxc.sourceforge.net/download/lxc/
>
> Don't forget to check the README in the directory ;)
>
>    -- Daniel



-- 
Have fun,
Xiaoming Zhang

Re: sysfs question

[Daniel Lezcano]

xiaoming.zhang wrote:
> On Thursday 11 September 2008 11:37:33 pm Daniel Lezcano wrote:
>> xiaoming.zhang wrote:
>>> On Thursday 11 September 2008 10:05:43 pm Mark Ryden wrote:
>>>> In fact, after looking more closely, I see that before that message
>>>> appears: Error: unmouting old /sys
>>>> ERROR unmounting old /sys: Invalid argument.
>>>> forcing unmount of /sys
>>>> switchroot...
>>> My experience is you'd better to find a sysfs patch, since the sysfs
>>> filesystem is required by ramdisk and some system utilities, e.g., system
>>> network configuration scripts.
>>>
>>> Patch for mm-tree can be found here:
>>> 	http://lxc.sourceforge.net/patches/2.6.26/
>>>
>>> This is what I used:
>>> http://lxc.sourceforge.net/patches/2.6.26/2.6.26-rc8-mm1-lxc1/broken-out/
>>> sysfs/
>>>
>>> I merged these 11 patches on Linux-2.6.26.1 though I don't understand
>>> these patches, luckily enough it worked for me.
>> As mentioned Benjamin, it is hard to boot a distro without sysfs. I
>> think it is a good idea to use the lxc patchset.
>>
>> You can use the latest version:
>>
>> http://lxc.sourceforge.net/patches/2.6.27/2.6.27-rc6-lxc1/
>>
> Thank you very much. And is there any patchset for Linux-2.6.26.* (not the 
> mm-tree)?

We worked most of the time sticked with the devel version of the kernel 
tree. The kernel which is the nearest of the version you are describing 
is 2.6.27-rc6-lxc1 which is not based on the -mm but on the 2.6.27 
release candidate. IMO, this is the most stable version of the LXC.

Re: sysfs question

[Benjamin Thery]

Hi Mark,

Indeed booting a distro without sysfs can be tricky because, for
example, initrd might need it (eg. Fedora).

IIRC, to boot without sysfs, in addition to the "root=" option,  you
have to create some devices nodes in advance in your /dev tree
(mainly the /dev/sda* ones, plus a bunch of others /dev/urandom,
/dev/null, /dev/console, /dev/tty).

mknod /dev/sda b 8 0
mknod /dev/sda1 b 8 1
...

But my advice to test netns is to apply the tagged directories sysfs
patchses. It is a lot easier (and complete).

Gregkh is merging the patchset to his tree today (he has added 6 out of
the 8 remaining patches this morning) :)
Once the patchset is completely merged I'll update the howto.

Also I can send you tarball too if you want. Which kernel version do you 
use?

Regards,
Benjamin


Mark Ryden wrote:
> Hello,
> I am trying to follow the
> Linux Containers - Network Namespace configuration instructions from
> http://lxc.sourceforge.net/network/configuration.php
> 
> 
> I had built a kernel with CONFIG_SYS=n and  CONFIG_NET_NS=y
> and CONFIG_VETH=y , etc, according to the instructions.
> 
> 
> Now, the CONFIG_SYSFS help text says:
> 
> sysfs is currently used by the block subsystem to mount the root
> partition. If sysfs is disabled you must specify the boot device on
> the kernel boot command line via its major and minor numbers. For
> example, "root=03:01" for /dev/hda1.
> 
> 
> So I added root=08,02 to my kernel boot parameter line and booted.
> 
> 
> it starts booting, but then gets:
> switchroot: mount failed: No such file or directory.
> Booting has failed.
> 
> 8 is the majoror number and 2 is the minor number of /dev/sda2, where I have
> my root partition.
> 
> Googling for this found the following, which not helped much:
> http://linux.derkeiler.com/Mailing-Lists/Kernel/2007-11/msg05032.html
> 
> Any ideas?
> Regards,
> Mark
> _______________________________________________
> Containers mailing list
> Containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
> https://lists.linux-foundation.org/mailman/listinfo/containers
> 
> 


-- 
B e n j a m i n   T h e r y  - BULL/DT/Open Software R&D

    http://www.bull.com

sysfs question

[Kurt Van Dijck]

Hi,

Within the socketcan project, we came into a situation that
might benefit with input from the netdev mailing list.

The main issue is the policy to add sysfs properties in
/sys/class/net/canX.

The reason for this is that cards (devices) with multiple network
interfaces may require properties per network.

An obvious property would be the 'channel number of the card'. Other
properties could be things like type of output circuitry, ..., rather
hardware specific.

I see currently 3 options:
1) such properties in /sys/class/net/canX would be allowed.
2) such properties would belong in /sys/class/net/canX/<subdirectory tbd>/
3) such properties would go somewhere else.

Some input with regard to sysfs policies would be helpfull.

Kurt

Re: sysfs question

[Stephen Hemminger]

On Thu, 12 Nov 2009 11:39:41 +0100
Kurt Van Dijck <kurt.van.dijck@eia.be> wrote:

> Hi,
> 
> Within the socketcan project, we came into a situation that
> might benefit with input from the netdev mailing list.
> 
> The main issue is the policy to add sysfs properties in
> /sys/class/net/canX.
> 
> The reason for this is that cards (devices) with multiple network
> interfaces may require properties per network.
> 
> An obvious property would be the 'channel number of the card'. Other
> properties could be things like type of output circuitry, ..., rather
> hardware specific.
> 
> I see currently 3 options:
> 1) such properties in /sys/class/net/canX would be allowed.
> 2) such properties would belong in /sys/class/net/canX/<subdirectory tbd>/
> 3) such properties would go somewhere else.
> 
> Some input with regard to sysfs policies would be helpfull.
> 
> Kurt

It sounds like the property you are proposing is a property of the
upper network layer not the hardware. Putting more properties in sysfs
is good if is hardware related, but awkward if it is really a protocol
attribute.

Re: sysfs question

[Oliver Hartkopp]

Stephen Hemminger wrote:
> On Thu, 12 Nov 2009 11:39:41 +0100
> Kurt Van Dijck <kurt.van.dijck@eia.be> wrote:
> 
>> Hi,
>>
>> Within the socketcan project, we came into a situation that
>> might benefit with input from the netdev mailing list.
>>
>> The main issue is the policy to add sysfs properties in
>> /sys/class/net/canX.
>>
>> The reason for this is that cards (devices) with multiple network
>> interfaces may require properties per network.
>>
>> An obvious property would be the 'channel number of the card'. Other
>> properties could be things like type of output circuitry, ..., rather
>> hardware specific.
>>
>> I see currently 3 options:
>> 1) such properties in /sys/class/net/canX would be allowed.
>> 2) such properties would belong in /sys/class/net/canX/<subdirectory tbd>/
>> 3) such properties would go somewhere else.
>>
>> Some input with regard to sysfs policies would be helpfull.
>>
>> Kurt
> 
> It sounds like the property you are proposing is a property of the
> upper network layer not the hardware. Putting more properties in sysfs
> is good if is hardware related, but awkward if it is really a protocol
> attribute.

Then it would be good here :-)

The problem that can occur here is:

You plug-in a PCMCIA CAN card that has two CAN controllers on-board.

That means, you're getting two CAN independed network interfaces can0 and can1
pointing to ONE pcmcia device. Both of the CAN netdevs may have different
bitrates or other CAN controller specific settings (like the type of output
circuitry Kurt mentioned).

Finally the PCMCIA card itself may contain a serial number and/or a license
information that needs to be made available.

It's definitely no upper network layer stuff.

Regards,
Oliver

Re: sysfs question

[Kurt Van Dijck]

On Thu, Nov 12, 2009 at 06:44:36PM +0100, Oliver Hartkopp wrote:
> Stephen Hemminger wrote:
> > On Thu, 12 Nov 2009 11:39:41 +0100
> > Kurt Van Dijck <kurt.van.dijck@eia.be> wrote:
> > 
[...]
> > 
> > It sounds like the property you are proposing is a property of the
> > upper network layer not the hardware. Putting more properties in sysfs
> > is good if is hardware related, but awkward if it is really a protocol
> > attribute.
> 
> Then it would be good here :-)
> 
[...]
> 
> It's definitely no upper network layer stuff.
> 
Ack. It's definitely datalink or even physical layer we're talking about.
> Regards,
> Oliver

I also encountered an issue with regard to the uevent that is generated
when a netdevice is registered.
If I add sysfs files before register_netdevice, the system complains on
creating the sysfs files.
If I add those after register_netdevice, the uevent is _seems_ to have
triggered userspace already, where the udev (in fact, I use another
home-brew one for boot speed) does not find the extra sysfs file.

Is there a mechanism to hold temporarily the uevent until after the
driver has registered some extra sysfs files?

Kurt

sysfs question

[Dennis Munsie]

quick question regarding sysfs and the framebuffer... I can add my  
own attributes without any problems, but they always show up with the  
device (/sys/class/graphics/fb0/device), not the rest of the  
framebuffer attributes (/sys/class/graphics/fb0).  Is there a good  
way to put them with the fb attributes?  or is this a no-no?

thanks!
dennis

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Re: sysfs question

[Luca]

Il Mon, Jul 24, 2006 at 09:47:59AM -0400, Dennis Munsie ha scritto: 
> quick question regarding sysfs and the framebuffer... I can add my  
> own attributes without any problems, but they always show up with the  
> device (/sys/class/graphics/fb0/device), not the rest of the  
> framebuffer attributes (/sys/class/graphics/fb0). Is there a good  
> way to put them with the fb attributes?

You have to attach the new attributes to the class_device instead of the
device. See class_device_create_file().
I don't know if it's a good idea tough: if the attributes are specific
to only one device it sounds more logical to attach them to the device.

Luca
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[PATCH] Fix USB suspend/resume crasher

[Benjamin Herrenschmidt]

This is my latest patch against current linus -git, it closes the IRQ
race and makes various other OHCI & EHCI code path safer vs.
suspend/resume. I've been able to (finally !) successfully suspend and
resume various Mac models, with or without USB mouse plugged, or
plugging while asleep, or unplugging while asleep etc... all without a
crash. There are still some races here or there in the USB code, but at
least the main cause of crash is now fixes by this patch (access to a
controller that has been suspended, due to either shared interrupts or
other code path).

I haven't fixed UHCI as I don't have any HW to test, though I hope I
haven't broken it neither. Alan, I would appreciate if you could have a
look.

This patch applies on top of the patch that moves the PowerMac specific
code out of ohci-pci.c to hcd-pci.c where it belongs. This patch isn't
upstream yet for reasons I don't fully understand (why does USB stuffs
has such a high latency for going upstream ?), I'm sending it as a reply
to this email for completeness.

Without this patch, you cannot reliably sleep/wakeup any recent Mac, and
I suspect PCs have some more sneaky issues too (they don't frankly crash
with machine checks because x86 tend to silently swallow PCI errors but
that won't last afaik, at least PCI Express will blow up in those
situations, but the USB code may still misbehave).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

Note that I REALLY want that in 2.6.15. 2.6.14 is already broken, though I
have a similar patch for it that some users have been successfully testing
and I don't want 2.6.15 to be broken too. So unless you have a major issue
with the patch as it is and it breaks something, I think it should be applied,
and I don't want to get into yet another 10000 email exchange discussion on
the merit of doing proper locking and why the current situation is broken...

Index: linux-serialfix/drivers/usb/core/hcd-pci.c
===================================================================
--- linux-serialfix.orig/drivers/usb/core/hcd-pci.c	2005-11-23 13:52:23.000000000 +1100
+++ linux-serialfix/drivers/usb/core/hcd-pci.c	2005-11-23 13:52:32.000000000 +1100
@@ -218,6 +218,7 @@
 			goto done;
 		}
 	}
+	synchronize_irq(dev->irq);
 
 	/* FIXME until the generic PM interfaces change a lot more, this
 	 * can't use PCI D1 and D2 states.  For example, the confusion
@@ -386,7 +387,7 @@
 
 	dev->dev.power.power_state = PMSG_ON;
 
-	hcd->saw_irq = 0;
+	clear_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
 
 	if (hcd->driver->resume) {
 		retval = hcd->driver->resume(hcd);
Index: linux-serialfix/drivers/usb/core/hcd.c
===================================================================
--- linux-serialfix.orig/drivers/usb/core/hcd.c	2005-11-23 13:47:45.000000000 +1100
+++ linux-serialfix/drivers/usb/core/hcd.c	2005-11-23 13:52:32.000000000 +1100
@@ -1315,11 +1315,12 @@
 	 * finish unlinking the initial failed usb_set_address()
 	 * or device descriptor fetch.
 	 */
-	if (!hcd->saw_irq && hcd->self.root_hub != urb->dev) {
+	if (!test_bit(HCD_FLAG_SAW_IRQ, &hcd->flags)
+	    && hcd->self.root_hub != urb->dev) {
 		dev_warn (hcd->self.controller, "Unlink after no-IRQ?  "
 			"Controller is probably using the wrong IRQ."
 			"\n");
-		hcd->saw_irq = 1;
+		set_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
 	}
 
 	urb->status = status;
@@ -1649,13 +1650,15 @@
 	struct usb_hcd		*hcd = __hcd;
 	int			start = hcd->state;
 
-	if (start == HC_STATE_HALT)
+	if (unlikely(start == HC_STATE_HALT ||
+	    !test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)))
 		return IRQ_NONE;
 	if (hcd->driver->irq (hcd, r) == IRQ_NONE)
 		return IRQ_NONE;
 
-	hcd->saw_irq = 1;
-	if (hcd->state == HC_STATE_HALT)
+	set_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
+
+	if (unlikely(hcd->state == HC_STATE_HALT))
 		usb_hc_died (hcd);
 	return IRQ_HANDLED;
 }
@@ -1768,6 +1771,8 @@
 
 	dev_info(hcd->self.controller, "%s\n", hcd->product_desc);
 
+	set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
+
 	/* till now HC has been in an indeterminate state ... */
 	if (hcd->driver->reset && (retval = hcd->driver->reset(hcd)) < 0) {
 		dev_err(hcd->self.controller, "can't reset\n");
Index: linux-serialfix/drivers/usb/core/hcd.h
===================================================================
--- linux-serialfix.orig/drivers/usb/core/hcd.h	2005-11-23 13:47:45.000000000 +1100
+++ linux-serialfix/drivers/usb/core/hcd.h	2005-11-23 13:52:32.000000000 +1100
@@ -72,7 +72,12 @@
 	 * hardware info/state
 	 */
 	const struct hc_driver	*driver;	/* hw-specific hooks */
-	unsigned		saw_irq : 1;
+
+	/* Flags that need to be manipulated atomically */
+	unsigned long		flags;
+#define HCD_FLAG_HW_ACCESSIBLE	0x00000001
+#define HCD_FLAG_SAW_IRQ	0x00000002
+
 	unsigned		can_wakeup:1;	/* hw supports wakeup? */
 	unsigned		remote_wakeup:1;/* sw should use wakeup? */
 	unsigned		rh_registered:1;/* is root hub registered? */
Index: linux-serialfix/drivers/usb/host/ehci-pci.c
===================================================================
--- linux-serialfix.orig/drivers/usb/host/ehci-pci.c	2005-11-23 13:47:45.000000000 +1100
+++ linux-serialfix/drivers/usb/host/ehci-pci.c	2005-11-23 13:52:32.000000000 +1100
@@ -244,22 +244,34 @@
 static int ehci_pci_suspend (struct usb_hcd *hcd, pm_message_t message)
 {
 	struct ehci_hcd		*ehci = hcd_to_ehci (hcd);
+	unsigned long		flags;
+	int			rc = 0;
 
 	if (time_before (jiffies, ehci->next_statechange))
 		msleep (100);
 
-#ifdef	CONFIG_USB_SUSPEND
-	(void) usb_suspend_device (hcd->self.root_hub);
-#else
-	usb_lock_device (hcd->self.root_hub);
-	(void) ehci_bus_suspend (hcd);
-	usb_unlock_device (hcd->self.root_hub);
-#endif
+	/* Root hub was already suspended. Disable irq emission and
+	 * mark HW unaccessible, bail out if RH has been resumed. Use
+	 * the spinlock to properly synchronize with possible pending
+	 * RH suspend or resume activity.
+	 *
+	 * This is still racy as hcd->state is manipulated outside of
+	 * any locks =P But that will be a different fix.
+	 */
+	spin_lock_irqsave (&ehci->lock, flags);
+	if (hcd->state != HC_STATE_SUSPENDED) {
+		rc = -EINVAL;
+		goto bail;
+	}
+	writel (0, &ehci->regs->intr_enable);
+	clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
+ bail:
+	spin_unlock_irqrestore (&ehci->lock, flags);
 
 	// save (PCI) FLADJ in case of Vaux power loss
 	// ... we'd only use it to handle clock skew
 
-	return 0;
+	return rc;
 }
 
 static int ehci_pci_resume (struct usb_hcd *hcd)
@@ -274,6 +286,8 @@
 	if (time_before (jiffies, ehci->next_statechange))
 		msleep (100);
 
+	set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
+
 	/* If any port is suspended (or owned by the companion),
 	 * we know we can/must resume the HC (and mustn't reset it).
 	 */
Index: linux-serialfix/drivers/usb/host/ehci-q.c
===================================================================
--- linux-serialfix.orig/drivers/usb/host/ehci-q.c	2005-11-23 13:47:45.000000000 +1100
+++ linux-serialfix/drivers/usb/host/ehci-q.c	2005-11-23 13:52:32.000000000 +1100
@@ -912,6 +912,7 @@
 	int			epnum;
 	unsigned long		flags;
 	struct ehci_qh		*qh = NULL;
+	int			rc = 0;
 
 	qtd = list_entry (qtd_list->next, struct ehci_qtd, qtd_list);
 	epnum = ep->desc.bEndpointAddress;
@@ -926,21 +927,28 @@
 #endif
 
 	spin_lock_irqsave (&ehci->lock, flags);
+	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
+			       &ehci_to_hcd(ehci)->flags))) {
+		rc = -ESHUTDOWN;
+		goto done;
+	}
+
 	qh = qh_append_tds (ehci, urb, qtd_list, epnum, &ep->hcpriv);
+	if (unlikely(qh == NULL)) {
+		rc = -ENOMEM;
+		goto done;
+	}
 
 	/* Control/bulk operations through TTs don't need scheduling,
 	 * the HC and TT handle it when the TT has a buffer ready.
 	 */
-	if (likely (qh != NULL)) {
-		if (likely (qh->qh_state == QH_STATE_IDLE))
-			qh_link_async (ehci, qh_get (qh));
-	}
+	if (likely (qh->qh_state == QH_STATE_IDLE))
+		qh_link_async (ehci, qh_get (qh));
+ done:
 	spin_unlock_irqrestore (&ehci->lock, flags);
-	if (unlikely (qh == NULL)) {
+	if (unlikely (qh == NULL))
 		qtd_list_free (ehci, urb, qtd_list);
-		return -ENOMEM;
-	}
-	return 0;
+	return rc;
 }
 
 /*-------------------------------------------------------------------------*/
Index: linux-serialfix/drivers/usb/host/ehci-sched.c
===================================================================
--- linux-serialfix.orig/drivers/usb/host/ehci-sched.c	2005-11-23 13:47:45.000000000 +1100
+++ linux-serialfix/drivers/usb/host/ehci-sched.c	2005-11-23 13:52:32.000000000 +1100
@@ -602,6 +602,12 @@
 
 	spin_lock_irqsave (&ehci->lock, flags);
 
+	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
+			       &ehci_to_hcd(ehci)->flags))) {
+		status = -ESHUTDOWN;
+		goto done;
+	}
+
 	/* get qh and force any scheduling errors */
 	INIT_LIST_HEAD (&empty);
 	qh = qh_append_tds (ehci, urb, &empty, epnum, &ep->hcpriv);
@@ -1456,7 +1462,11 @@
 
 	/* schedule ... need to lock */
 	spin_lock_irqsave (&ehci->lock, flags);
-	status = iso_stream_schedule (ehci, urb, stream);
+	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
+			       &ehci_to_hcd(ehci)->flags)))
+		status = -ESHUTDOWN;
+	else
+		status = iso_stream_schedule (ehci, urb, stream);
  	if (likely (status == 0))
 		itd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
 	spin_unlock_irqrestore (&ehci->lock, flags);
@@ -1815,7 +1825,11 @@
 
 	/* schedule ... need to lock */
 	spin_lock_irqsave (&ehci->lock, flags);
-	status = iso_stream_schedule (ehci, urb, stream);
+	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
+			       &ehci_to_hcd(ehci)->flags)))
+		status = -ESHUTDOWN;
+	else
+		status = iso_stream_schedule (ehci, urb, stream);
  	if (status == 0)
 		sitd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
 	spin_unlock_irqrestore (&ehci->lock, flags);
Index: linux-serialfix/drivers/usb/host/ohci-hcd.c
===================================================================
--- linux-serialfix.orig/drivers/usb/host/ohci-hcd.c	2005-11-23 13:47:45.000000000 +1100
+++ linux-serialfix/drivers/usb/host/ohci-hcd.c	2005-11-23 13:57:06.000000000 +1100
@@ -115,7 +115,7 @@
 
 /*-------------------------------------------------------------------------*/
 
-// #define OHCI_VERBOSE_DEBUG	/* not always helpful */
+#undef OHCI_VERBOSE_DEBUG	/* not always helpful */
 
 /* For initializing controller (mask in an HCFS mode too) */
 #define	OHCI_CONTROL_INIT 	OHCI_CTRL_CBSR
@@ -253,6 +253,10 @@
 	spin_lock_irqsave (&ohci->lock, flags);
 
 	/* don't submit to a dead HC */
+	if (!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)) {
+		retval = -ENODEV;
+		goto fail;
+	}
 	if (!HC_IS_RUNNING(hcd->state)) {
 		retval = -ENODEV;
 		goto fail;
Index: linux-serialfix/drivers/usb/host/ohci-hub.c
===================================================================
--- linux-serialfix.orig/drivers/usb/host/ohci-hub.c	2005-11-23 13:47:45.000000000 +1100
+++ linux-serialfix/drivers/usb/host/ohci-hub.c	2005-11-23 13:54:04.000000000 +1100
@@ -53,6 +53,11 @@
 
 	spin_lock_irqsave (&ohci->lock, flags);
 
+	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags))) {
+		spin_unlock_irqrestore (&ohci->lock, flags);
+		return -ESHUTDOWN;
+	}
+
 	ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
 	switch (ohci->hc_control & OHCI_CTRL_HCFS) {
 	case OHCI_USB_RESUME:
@@ -140,11 +145,19 @@
 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
 	u32			temp, enables;
 	int			status = -EINPROGRESS;
+	unsigned long		flags;
 
 	if (time_before (jiffies, ohci->next_statechange))
 		msleep(5);
 
-	spin_lock_irq (&ohci->lock);
+	spin_lock_irqsave (&ohci->lock, flags);
+
+	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags))) {
+		spin_unlock_irqrestore (&ohci->lock, flags);
+		return -ESHUTDOWN;
+	}
+
+
 	ohci->hc_control = ohci_readl (ohci, &ohci->regs->control);
 
 	if (ohci->hc_control & (OHCI_CTRL_IR | OHCI_SCHED_ENABLES)) {
@@ -179,7 +192,7 @@
 		ohci_dbg (ohci, "lost power\n");
 		status = -EBUSY;
 	}
-	spin_unlock_irq (&ohci->lock);
+	spin_unlock_irqrestore (&ohci->lock, flags);
 	if (status == -EBUSY) {
 		(void) ohci_init (ohci);
 		return ohci_restart (ohci);
@@ -297,8 +310,8 @@
 	/* handle autosuspended root:  finish resuming before
 	 * letting khubd or root hub timer see state changes.
 	 */
-	if ((ohci->hc_control & OHCI_CTRL_HCFS) != OHCI_USB_OPER
-			|| !HC_IS_RUNNING(hcd->state)) {
+	if (unlikely((ohci->hc_control & OHCI_CTRL_HCFS) != OHCI_USB_OPER
+		     || !HC_IS_RUNNING(hcd->state))) {
 		can_suspend = 0;
 		goto done;
 	}
@@ -508,6 +521,9 @@
 	u32		temp;
 	int		retval = 0;
 
+	if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)))
+		return -ESHUTDOWN;
+
 	switch (typeReq) {
 	case ClearHubFeature:
 		switch (wValue) {
Index: linux-serialfix/drivers/usb/host/ohci-pci.c
===================================================================
--- linux-serialfix.orig/drivers/usb/host/ohci-pci.c	2005-11-23 13:52:23.000000000 +1100
+++ linux-serialfix/drivers/usb/host/ohci-pci.c	2005-11-23 13:52:32.000000000 +1100
@@ -114,12 +114,35 @@
 
 static int ohci_pci_suspend (struct usb_hcd *hcd, pm_message_t message)
 {
-	return 0;
+	struct ohci_hcd	*ohci = hcd_to_ohci (hcd);
+	unsigned long	flags;
+	int		rc = 0;
+
+	/* Root hub was already suspended. Disable irq emission and
+	 * mark HW unaccessible, bail out if RH has been resumed. Use
+	 * the spinlock to properly synchronize with possible pending
+	 * RH suspend or resume activity.
+	 *
+	 * This is still racy as hcd->state is manipulated outside of
+	 * any locks =P But that will be a different fix.
+	 */
+	spin_lock_irqsave (&ohci->lock, flags);
+	if (hcd->state != HC_STATE_SUSPENDED) {
+		rc = -EINVAL;
+		goto bail;
+	}
+	ohci_writel(ohci, OHCI_INTR_MIE, &ohci->regs->intrdisable);
+	clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
+ bail:
+	spin_unlock_irqrestore (&ohci->lock, flags);
+
+	return rc;
 }
 
 
 static int ohci_pci_resume (struct usb_hcd *hcd)
 {
+	set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
 	usb_hcd_resume_root_hub(hcd);
 	return 0;
 }

Re: [PATCH] Fix USB suspend/resume crasher

[Rafael J. Wysocki]

[-- Attachment #1: Type: text/plain, Size: 5195 bytes --]

Hi,

On Wednesday, 23 of November 2005 04:08, Benjamin Herrenschmidt wrote:
> This is my latest patch against current linus -git, it closes the IRQ
> race and makes various other OHCI & EHCI code path safer vs.
> suspend/resume. I've been able to (finally !) successfully suspend and
> resume various Mac models, with or without USB mouse plugged, or
> plugging while asleep, or unplugging while asleep etc... all without a
> crash. There are still some races here or there in the USB code, but at
> least the main cause of crash is now fixes by this patch (access to a
> controller that has been suspended, due to either shared interrupts or
> other code path).
> 
> I haven't fixed UHCI as I don't have any HW to test, though I hope I
> haven't broken it neither. Alan, I would appreciate if you could have a
> look.
> 
> This patch applies on top of the patch that moves the PowerMac specific
> code out of ohci-pci.c to hcd-pci.c where it belongs. This patch isn't
> upstream yet for reasons I don't fully understand (why does USB stuffs
> has such a high latency for going upstream ?), I'm sending it as a reply
> to this email for completeness.
> 
> Without this patch, you cannot reliably sleep/wakeup any recent Mac, and
> I suspect PCs have some more sneaky issues too (they don't frankly crash
> with machine checks because x86 tend to silently swallow PCI errors but
> that won't last afaik, at least PCI Express will blow up in those
> situations, but the USB code may still misbehave).

Unfortunately with this patch the EHCI controller in my box (Asus L5D,
x86-64 kernel) does not resume from suspend.  Appended is the relevant
snippet from the serial console log (EHCI is the only device using IRQ #5).

Greetings,
Rafael


PM: Image restored successfully.
ohci_hcd 0000:00:02.0: PCI D0, from previous PCI D3
ACPI: PCI Interrupt 0000:00:02.0[A] -> Link [LUS0] -> GSI 11 (level, low) -> IRQ 11
PCI: Setting latency timer of device 0000:00:02.0 to 64
ohci_hcd 0000:00:02.1: PCI D0, from previous PCI D3
ACPI: PCI Interrupt 0000:00:02.1[B] -> Link [LUS1] -> GSI 11 (level, low) -> IRQ 11
PCI: Setting latency timer of device 0000:00:02.1 to 64
ehci_hcd 0000:00:02.2: PCI D0, from previous PCI D3
ACPI: PCI Interrupt 0000:00:02.2[C] -> Link [LUS2] -> GSI 5 (level, low) -> IRQ 5
PCI: Setting latency timer of device 0000:00:02.2 to 64
ehci_hcd 0000:00:02.2: lost power, restarting
usb usb3: root hub lost power or was reset
ehci_hcd 0000:00:02.2: reset command 080b02 park=3 ithresh=8 period=1024 Reset HALT
ehci_hcd 0000:00:02.2: debug port 1
ehci_hcd 0000:00:02.2: capability 1000001 at a0
PCI: cache line size of 64 is not supported by device 0000:00:02.2
ehci_hcd 0000:00:02.2: reset command 080b02 park=3 ithresh=8 period=1024 Reset HALT
ehci_hcd 0000:00:02.2: init command 010009 (park)=0 ithresh=1 period=256 RUN
ehci_hcd 0000:00:02.2: USB 2.0 started, EHCI 1.00, driver 10 Dec 2004
ACPI: PCI Interrupt 0000:00:06.0[A] -> Link [LAUI] -> GSI 10 (level, low) -> IRQ 10
PCI: Setting latency timer of device 0000:00:06.0 to 64
irq 5: nobody cared (try booting with the "irqpoll" option)

Call Trace: <IRQ> <ffffffff80250c3e>{add_preempt_count+94} <ffffffff8015a878>{__report_bad_irq+56}
       <ffffffff8015aab4>{note_interrupt+484} <ffffffff8015a317>{__do_IRQ+199}
       <ffffffff801110f7>{do_IRQ+55} <ffffffff8010f100>{ret_from_intr+0}
       <ffffffff8010fb02>{call_softirq+30} <ffffffff80138714>{__do_softirq+68}
       <ffffffff801386ff>{__do_softirq+47} <ffffffff8010fb02>{call_softirq+30}
       <ffffffff801110b5>{do_softirq+53} <ffffffff8013849f>{irq_exit+63}
       <ffffffff801110fc>{do_IRQ+60} <ffffffff8010f100>{ret_from_intr+0}
        <EOI> <ffffffff802c183a>{serial8250_console_write+186}
       <ffffffff80132dad>{release_console_sem+333} <ffffffff80133587>{vprintk+775}
       <ffffffff80133682>{printk+162} <ffffffff80133682>{printk+162}
       <ffffffff8036003d>{_spin_unlock_irqrestore+29} <ffffffff80252c31>{pci_bus_read_config_byte+113}
       <ffffffff802ed6fe>{pcibios_set_master+110} <ffffffff80255415>{pci_set_master+85}
       <ffffffff88180eb7>{:snd_intel8x0:intel8x0_resume+39}
       <ffffffff8812a9e7>{:snd:snd_card_pci_resume+55} <ffffffff80256c74>{pci_device_resume+36}
       <ffffffff802d5cdd>{resume_device+157} <ffffffff802d5e23>{dpm_resume+147}
       <ffffffff802d5e90>{device_resume+32} <ffffffff80153508>{pm_suspend_disk+296}
       <ffffffff80150f10>{enter_state+112} <ffffffff80151147>{state_store+119}
       <ffffffff801bfdd4>{subsys_attr_store+36} <ffffffff801c025a>{sysfs_write_file+202}
       <ffffffff8017fb09>{vfs_write+233} <ffffffff8017fcb0>{sys_write+80}
       <ffffffff8010eb5e>{system_call+126}
---------------------------
| preempt count: 00010103 ]
| 3 level deep critical section nesting:
----------------------------------------
.. [<ffffffff801332a4>] .... vprintk+0x24/0x360
.....[<ffffffff80133682>] ..   ( <= printk+0xa2/0xb0)
.. [<ffffffff80360176>] .... _spin_lock+0x16/0x30
.....[<ffffffff8015a2fc>] ..   ( <= __do_IRQ+0xac/0x120)
.. [<ffffffff80360176>] .... _spin_lock+0x16/0x30
.....[<ffffffff8015a2fc>] ..   ( <= __do_IRQ+0xac/0x120)

handlers:
[<ffffffff80260970>] (usb_hcd_irq+0x0/0x70)
Disabling IRQ #5


[-- Attachment #2: lspci-v.log --]
[-- Type: text/x-log, Size: 6384 bytes --]

0000:00:00.0 Host bridge: nVidia Corporation nForce3 Host Bridge (rev a4)
	Subsystem: ASUSTeK Computer Inc.: Unknown device 80c5
	Flags: bus master, 66Mhz, fast devsel, latency 0
	Memory at e8000000 (32-bit, prefetchable) [size=128M]
	Capabilities: <available only to root>

0000:00:01.0 ISA bridge: nVidia Corporation nForce3 LPC Bridge (rev f6)
	Subsystem: ASUSTeK Computer Inc.: Unknown device 80c5
	Flags: bus master, 66Mhz, fast devsel, latency 0

0000:00:01.1 SMBus: nVidia Corporation nForce3 SMBus (rev a4)
	Subsystem: ASUSTeK Computer Inc.: Unknown device 80c5
	Flags: 66Mhz, fast devsel
	I/O ports at 5000 [size=64]
	I/O ports at 5040 [size=64]
	Capabilities: <available only to root>

0000:00:02.0 USB Controller: nVidia Corporation nForce3 USB 1.1 (rev a5) (prog-if 10 [OHCI])
	Subsystem: ASUSTeK Computer Inc.: Unknown device 1858
	Flags: bus master, 66Mhz, fast devsel, latency 0, IRQ 11
	Memory at febfb000 (32-bit, non-prefetchable) [size=4K]
	Capabilities: <available only to root>

0000:00:02.1 USB Controller: nVidia Corporation nForce3 USB 1.1 (rev a5) (prog-if 10 [OHCI])
	Subsystem: ASUSTeK Computer Inc.: Unknown device 1858
	Flags: bus master, 66Mhz, fast devsel, latency 0, IRQ 11
	Memory at febfc000 (32-bit, non-prefetchable) [size=4K]
	Capabilities: <available only to root>

0000:00:02.2 USB Controller: nVidia Corporation nForce3 USB 2.0 (rev a2) (prog-if 20 [EHCI])
	Subsystem: ASUSTeK Computer Inc.: Unknown device 1859
	Flags: bus master, 66Mhz, fast devsel, latency 0, IRQ 5
	Memory at febfdc00 (32-bit, non-prefetchable) [size=256]
	Capabilities: <available only to root>

0000:00:06.0 Multimedia audio controller: nVidia Corporation nForce3 Audio (rev a2)
	Subsystem: ASUSTeK Computer Inc.: Unknown device 1853
	Flags: bus master, 66Mhz, fast devsel, latency 0, IRQ 10
	I/O ports at e800 [size=256]
	I/O ports at ec00 [size=128]
	Memory at febff000 (32-bit, non-prefetchable) [size=4K]
	Capabilities: <available only to root>

0000:00:08.0 IDE interface: nVidia Corporation nForce3 IDE (rev a5) (prog-if 8a [Master SecP PriP])
	Subsystem: ASUSTeK Computer Inc.: Unknown device 185a
	Flags: bus master, 66Mhz, fast devsel, latency 0
	I/O ports at ffa0 [size=16]
	Capabilities: <available only to root>

0000:00:0a.0 PCI bridge: nVidia Corporation nForce3 PCI Bridge (rev a2) (prog-if 00 [Normal decode])
	Flags: bus master, 66Mhz, fast devsel, latency 0
	Bus: primary=00, secondary=02, subordinate=04, sec-latency=128
	I/O behind bridge: 0000b000-0000dfff
	Memory behind bridge: f8a00000-feafffff
	Prefetchable memory behind bridge: 40000000-43ffffff

0000:00:0b.0 PCI bridge: nVidia Corporation nForce3 AGP Bridge (rev a4) (prog-if 00 [Normal decode])
	Flags: bus master, 66Mhz, medium devsel, latency 64
	Bus: primary=00, secondary=01, subordinate=01, sec-latency=64
	Memory behind bridge: f6900000-f89fffff
	Prefetchable memory behind bridge: c6800000-e67fffff

0000:00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
	Flags: fast devsel
	Capabilities: <available only to root>

0000:00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
	Flags: fast devsel

0000:00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
	Flags: fast devsel

0000:00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
	Flags: fast devsel

0000:01:00.0 VGA compatible controller: nVidia Corporation NV31M [GeForce FX Go5650] (rev a1) (prog-if 00 [VGA])
	Subsystem: ASUSTeK Computer Inc.: Unknown device 1852
	Flags: bus master, 66Mhz, medium devsel, latency 64, IRQ 11
	Memory at f7000000 (32-bit, non-prefetchable) [size=16M]
	Memory at d0000000 (32-bit, prefetchable) [size=256M]
	Expansion ROM at f89e0000 [disabled] [size=128K]
	Capabilities: <available only to root>

0000:02:00.0 Ethernet controller: Marvell Technology Group Ltd. Gigabit Ethernet Controller (rev 13)
	Subsystem: ASUSTeK Computer Inc. Marvell 88E8001 Gigabit Ethernet Controller (Asus)
	Flags: bus master, 66Mhz, medium devsel, latency 64, IRQ 10
	Memory at feaf8000 (32-bit, non-prefetchable) [size=16K]
	I/O ports at d800 [size=256]
	Expansion ROM at feac0000 [disabled] [size=128K]
	Capabilities: <available only to root>

0000:02:01.0 CardBus bridge: Ricoh Co Ltd RL5c476 II (rev ab)
	Subsystem: ASUSTeK Computer Inc.: Unknown device 1854
	Flags: bus master, medium devsel, latency 168, IRQ 11
	Memory at fd200000 (32-bit, non-prefetchable) [size=4K]
	Bus: primary=02, secondary=03, subordinate=06, sec-latency=176
	Memory window 0: 40000000-41fff000 (prefetchable)
	Memory window 1: fc600000-fd1ff000
	I/O window 0: 0000b000-0000b0ff
	I/O window 1: 0000b400-0000b4ff
	16-bit legacy interface ports at 0001

0000:02:01.1 CardBus bridge: Ricoh Co Ltd RL5c476 II (rev ab)
	Subsystem: ASUSTeK Computer Inc.: Unknown device 1854
	Flags: bus master, medium devsel, latency 168, IRQ 11
	Memory at fa200000 (32-bit, non-prefetchable) [size=4K]
	Bus: primary=02, secondary=07, subordinate=0a, sec-latency=176
	Memory window 0: 42000000-43fff000 (prefetchable)
	Memory window 1: f9600000-fa1ff000
	I/O window 0: 0000b800-0000b8ff
	I/O window 1: 0000bc00-0000bcff
	16-bit legacy interface ports at 0001

0000:02:01.2 FireWire (IEEE 1394): Ricoh Co Ltd R5C552 IEEE 1394 Controller (rev 03) (prog-if 10 [OHCI])
	Subsystem: ASUSTeK Computer Inc.: Unknown device 1857
	Flags: bus master, medium devsel, latency 64, IRQ 10
	Memory at feafd000 (32-bit, non-prefetchable) [size=2K]
	Capabilities: <available only to root>

0000:02:01.3 System peripheral: Ricoh Co Ltd: Unknown device 0576 (rev 01)
	Subsystem: ASUSTeK Computer Inc.: Unknown device 185b
	Flags: medium devsel, IRQ 11
	Memory at feafd800 (32-bit, non-prefetchable) [size=256]
	Capabilities: <available only to root>

0000:02:01.4 System peripheral: Ricoh Co Ltd: Unknown device 0592
	Subsystem: ASUSTeK Computer Inc.: Unknown device 185c
	Flags: medium devsel, IRQ 11
	Memory at feafdc00 (32-bit, non-prefetchable) [size=256]
	Capabilities: <available only to root>

0000:02:02.0 Network controller: Broadcom Corporation BCM4306 802.11b/g Wireless LAN Controller (rev 03)
	Subsystem: ASUSTeK Computer Inc.: Unknown device 120f
	Flags: bus master, fast devsel, latency 64, IRQ 11
	Memory at feafe000 (32-bit, non-prefetchable) [size=8K]
	Capabilities: <available only to root>

sysfs question

[JaniD++]

Hello list,

I have searching the bottleneck of my system, and this is important to know
what is the 4. and the 8. number from this files exactly:

/sys/block/*/stat

Thanks,

Janos