[PATCH] USB BIOS early handoff only when the we the driver is configured

[PATCH] USB BIOS early handoff only when the we the driver is configured

[David Engraf]

When CONFIG_USB_UHCI_HCD, CONFIG_USB_OHCI_HCD or CONFIG_USB_EHCI_HCD is
not configured we don't need to call the quirk_usb_handoff_xxxx function
in driver/usb/host/pci_quiks.c.

I think the kernel shouldn't take the control over the usb controller
when we don't have the driver for it,
so with this patch the kernel takes the control only when the driver is
configured.


linux-2.6.22.1

diff -puN drivers/usb/host/pci-quirks_orig.c drivers/usb/host/pci-quirks.c
--- drivers/usb/host/pci-quirks_orig.c    2007-07-10 20:56:30.000000000
+0200
+++ drivers/usb/host/pci-quirks.c    2007-07-31 09:55:28.000000000 +0200
@@ -142,6 +142,7 @@ static inline int io_type_enabled(struct
 #define pio_enabled(dev) io_type_enabled(dev, PCI_COMMAND_IO)
 #define mmio_enabled(dev) io_type_enabled(dev, PCI_COMMAND_MEMORY)
 
+#ifdef CONFIG_USB_UHCI_HCD
 static void __devinit quirk_usb_handoff_uhci(struct pci_dev *pdev)
 {
     unsigned long base = 0;
@@ -159,12 +160,14 @@ static void __devinit quirk_usb_handoff_
     if (base)
         uhci_check_and_reset_hc(pdev, base);
 }
+#endif
 
 static int __devinit mmio_resource_enabled(struct pci_dev *pdev, int idx)
 {
     return pci_resource_start(pdev, idx) && mmio_enabled(pdev);
 }
 
+#ifdef CONFIG_USB_OHCI_HCD
 static void __devinit quirk_usb_handoff_ohci(struct pci_dev *pdev)
 {
     void __iomem *base;
@@ -209,7 +212,9 @@ static void __devinit quirk_usb_handoff_
 
     iounmap(base);
 }
+#endif
 
+#ifdef CONFIG_USB_EHCI_HCD
 static void __devinit quirk_usb_disable_ehci(struct pci_dev *pdev)
 {
     int wait_time, delta;
@@ -346,16 +351,24 @@ static void __devinit quirk_usb_disable_
 
     return;
 }
-
+#endif
 
 
 static void __devinit quirk_usb_early_handoff(struct pci_dev *pdev)
 {
+#ifdef CONFIG_USB_UHCI_HCD
     if (pdev->class == PCI_CLASS_SERIAL_USB_UHCI)
         quirk_usb_handoff_uhci(pdev);
-    else if (pdev->class == PCI_CLASS_SERIAL_USB_OHCI)
+#endif
+
+#ifdef CONFIG_USB_OHCI_HCD
+    if (pdev->class == PCI_CLASS_SERIAL_USB_OHCI)
         quirk_usb_handoff_ohci(pdev);
-    else if (pdev->class == PCI_CLASS_SERIAL_USB_EHCI)
+#endif
+
+#ifdef CONFIG_USB_EHCI_HCD
+    if (pdev->class == PCI_CLASS_SERIAL_USB_EHCI)
         quirk_usb_disable_ehci(pdev);
+#endif
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, quirk_usb_early_handoff);


Thanks

David Engraf

 

 
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Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[Alan Stern]

On Tue, 31 Jul 2007, David Engraf wrote:

> When CONFIG_USB_UHCI_HCD, CONFIG_USB_OHCI_HCD or CONFIG_USB_EHCI_HCD is
> not configured we don't need to call the quirk_usb_handoff_xxxx function
> in driver/usb/host/pci_quiks.c.
> 
> I think the kernel shouldn't take the control over the usb controller
> when we don't have the driver for it,
> so with this patch the kernel takes the control only when the driver is
> configured.

Have you found a system where this really improves behavior or is it 
just theoretical?

There _is_ a theoretical reason for running the handoff routines even 
when the corresponding driver isn't configured.  Namely, at startup the 
controller will be in some undetermined state as a result of usage by 
the firmware.  Resetting it to a known idle state is a good idea.

Bear in mind that on some systems, not performing the handoff has
caused interrupt storms during startup.

Alan Stern

Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[David Engraf]

At the moment I have a Jetway/VIA Mainboard which seems to have a
problem with the handoff.
Evenwhen I wait about 20 seconds the EHCI_USBLEGSUP_BIOS flag is not
cleared. I think this is a BIOS
bug and I will have to talk to Jetway/VIA.
On the other hand, I don't need the EHCI controller in my kernel, so I
think the kernel shouldn't take the
handover for the EHCI controller like other OS which do not have an usb
driver and so don't know that
there is a EHCI_USBLEGSUP_BIOS flag which should be cleared.

David Engraf


Alan Stern schrieb:
> On Tue, 31 Jul 2007, David Engraf wrote:
>
>   
>> When CONFIG_USB_UHCI_HCD, CONFIG_USB_OHCI_HCD or CONFIG_USB_EHCI_HCD is
>> not configured we don't need to call the quirk_usb_handoff_xxxx function
>> in driver/usb/host/pci_quiks.c.
>>
>> I think the kernel shouldn't take the control over the usb controller
>> when we don't have the driver for it,
>> so with this patch the kernel takes the control only when the driver is
>> configured.
>>     
>
> Have you found a system where this really improves behavior or is it 
> just theoretical?
>
> There _is_ a theoretical reason for running the handoff routines even 
> when the corresponding driver isn't configured.  Namely, at startup the 
> controller will be in some undetermined state as a result of usage by 
> the firmware.  Resetting it to a known idle state is a good idea.
>
> Bear in mind that on some systems, not performing the handoff has
> caused interrupt storms during startup.
>
> Alan Stern
>
>   
>

-- 
Mit freundlichen Grüßen

 

David Engraf

 

 
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Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[Greg KH]

On Wed, Aug 01, 2007 at 09:21:12AM +0200, David Engraf wrote:
> At the moment I have a Jetway/VIA Mainboard which seems to have a
> problem with the handoff.
> Evenwhen I wait about 20 seconds the EHCI_USBLEGSUP_BIOS flag is not
> cleared. I think this is a BIOS
> bug and I will have to talk to Jetway/VIA.

This sounds like a BIOS bug.

> On the other hand, I don't need the EHCI controller in my kernel, so I
> think the kernel shouldn't take the
> handover for the EHCI controller like other OS which do not have an usb
> driver and so don't know that
> there is a EHCI_USBLEGSUP_BIOS flag which should be cleared.

We need to do this early to handle a wide range of machines that do very
nasty things if we do not grab the device as early as possible.  Even if
we do not ever get around to loading that usb driver.

Yeah, hardware sucks at times :(

thanks,

greg k-h

Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[David Engraf]

Greg KH schrieb:
> On Wed, Aug 01, 2007 at 09:21:12AM +0200, David Engraf wrote:
>   
>> At the moment I have a Jetway/VIA Mainboard which seems to have a
>> problem with the handoff.
>> Evenwhen I wait about 20 seconds the EHCI_USBLEGSUP_BIOS flag is not
>> cleared. I think this is a BIOS
>> bug and I will have to talk to Jetway/VIA.
>>     
>
> This sounds like a BIOS bug.
>   
I think so too and I have to talk to Jetway/VIA what there is going wrong.
>   
>> On the other hand, I don't need the EHCI controller in my kernel, so I
>> think the kernel shouldn't take the
>> handover for the EHCI controller like other OS which do not have an usb
>> driver and so don't know that
>> there is a EHCI_USBLEGSUP_BIOS flag which should be cleared.
>>     
>
> We need to do this early to handle a wide range of machines that do very
> nasty things if we do not grab the device as early as possible.  Even if
> we do not ever get around to loading that usb driver.
>
> Yeah, hardware sucks at times :(
>
>   
Ok, but when we don't habe the driver for the usb controller, I think
the BIOS should control it because
maybe the BIOS found for example a keyboard or mouse and emulates it as
an PS2 keayboard/mouse,
so we could use it without the usb driver. I think that's why they
developed the handoff feature.
Are there any known hardware which has problems when we disable the handoff?

> thanks,
>
> greg k-h
>   

Thanks

 
David Engraf

 

 
Netcom Sicherheitstechnik GmbH
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Tel: 	+49 6131 6305 0
Fax: 	+49 6131 6305 40
Email: 	david.engraf@netcom.eu

 
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Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[Alan Stern]

On Wed, 1 Aug 2007, David Engraf wrote:

> At the moment I have a Jetway/VIA Mainboard which seems to have a problem
> with the handoff. Even
> when I wait about 20 seconds the EHCI_USBLEGSUP_BIOS flag is not cleared.
> I think this is a BIOS
> bug and I will have to talk to Jetway/VIA.

I have the same problem on my Intel motherboard.  Which is surprising, 
considering that Intel invented the BIOS-handoff technique.

> On the other hand, I don't need the EHCI controller in my kernel, so I
> think the kernel shouldn't take the
> handover for the EHCI controller like other OS which do not have an usb
> driver and so don't know that
> there is a EHCI_USBLEGSUP_BIOS flag which should be cleared.

There ought to be a solution to satisfy everybody.  For instance, you 
could add a Kconfig flag for enabling USB handoff, and make it be 
selected automatically if any of the PCI USB drivers are configured.

Alan Stern

Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[David Engraf]

Alan Stern schrieb:
> On Wed, 1 Aug 2007, David Engraf wrote:
>
>   
>> At the moment I have a Jetway/VIA Mainboard which seems to have a problem
>> with the handoff. Even
>> when I wait about 20 seconds the EHCI_USBLEGSUP_BIOS flag is not cleared.
>> I think this is a BIOS
>> bug and I will have to talk to Jetway/VIA.
>>     
>
> I have the same problem on my Intel motherboard.  Which is surprising, 
> considering that Intel invented the BIOS-handoff technique.
>
>   
Ok, so even Intel has problems with the handoff.
>> On the other hand, I don't need the EHCI controller in my kernel, so I
>> think the kernel shouldn't take the
>> handover for the EHCI controller like other OS which do not have an usb
>> driver and so don't know that
>> there is a EHCI_USBLEGSUP_BIOS flag which should be cleared.
>>     
>
> There ought to be a solution to satisfy everybody.  For instance, you 
> could add a Kconfig flag for enabling USB handoff, and make it be 
> selected automatically if any of the PCI USB drivers are configured.
>
> Alan Stern
>
>   
This would be solution too, but what if someone uses the uhci controller
and don't want the
ehci. So a single Kconfig flag wouldn't be enough, we have to add 3
flags for uchi, ohci and
ehci. I think this maybe a little bit difficult when configuring the kernel.
The best solution would be when we could use the CONFIG_USB_xxxx_HCD
flag, but it
seems that some hardware has problems when we disable the handoff and
let the BIOS
control the usb controller. Do you know any of this hardware?

Thanks

 
David Engraf

 

 
Netcom Sicherheitstechnik GmbH
Rheinallee 189
55120 Mainz
Tel: 	+49 6131 6305 0
Fax: 	+49 6131 6305 40
Email: 	david.engraf@netcom.eu

 
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Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[Alan Stern]

On Thu, 2 Aug 2007, David Engraf wrote:

> This would be solution too, but what if someone uses the uhci controller
> and don't want the
> ehci. So a single Kconfig flag wouldn't be enough, we have to add 3
> flags for uchi, ohci and
> ehci. I think this maybe a little bit difficult when configuring the kernel.
> The best solution would be when we could use the CONFIG_USB_xxxx_HCD
> flag, but it
> seems that some hardware has problems when we disable the handoff and
> let the BIOS
> control the usb controller. Do you know any of this hardware?

The email messages are hidden in the depths of the linux-usb-devel 
archives.  Maybe you can find them by checking the Git history for 
drivers/usb/host/pci-quirks.c, finding the dates for patches that 
affected the handoff code, and then searching through the archives near 
those dates.

IIRC the problems arose on some MIPS machines.  And I don't think the 
problem involved letting the firmware manage the USB controller; I 
think the problem came when the controller driver tried to do the 
handoff later on.

Alan Stern

Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[Greg KH]

On Thu, Aug 02, 2007 at 10:32:21AM -0400, Alan Stern wrote:
> On Thu, 2 Aug 2007, David Engraf wrote:
> 
> > This would be solution too, but what if someone uses the uhci controller
> > and don't want the
> > ehci. So a single Kconfig flag wouldn't be enough, we have to add 3
> > flags for uchi, ohci and
> > ehci. I think this maybe a little bit difficult when configuring the kernel.
> > The best solution would be when we could use the CONFIG_USB_xxxx_HCD
> > flag, but it
> > seems that some hardware has problems when we disable the handoff and
> > let the BIOS
> > control the usb controller. Do you know any of this hardware?
> 
> The email messages are hidden in the depths of the linux-usb-devel 
> archives.  Maybe you can find them by checking the Git history for 
> drivers/usb/host/pci-quirks.c, finding the dates for patches that 
> affected the handoff code, and then searching through the archives near 
> those dates.
> 
> IIRC the problems arose on some MIPS machines.  And I don't think the 
> problem involved letting the firmware manage the USB controller; I 
> think the problem came when the controller driver tried to do the 
> handoff later on.

It wasn't just MIPS.  IBM has a very popular blade system that has huge
issues with this, and I think there are some other IBM systems based on
the same BIOS that also do bad things if we don't grab the USB
controller away from the BIOS as soon as possible (nasty interrupt and
other messes happen...)

thanks,

greg k-h

Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[David Engraf]

Greg KH schrieb:
> On Thu, Aug 02, 2007 at 10:32:21AM -0400, Alan Stern wrote:
>   
>> On Thu, 2 Aug 2007, David Engraf wrote:
>>
>>     
>>> This would be solution too, but what if someone uses the uhci controller
>>> and don't want the
>>> ehci. So a single Kconfig flag wouldn't be enough, we have to add 3
>>> flags for uchi, ohci and
>>> ehci. I think this maybe a little bit difficult when configuring the kernel.
>>> The best solution would be when we could use the CONFIG_USB_xxxx_HCD
>>> flag, but it
>>> seems that some hardware has problems when we disable the handoff and
>>> let the BIOS
>>> control the usb controller. Do you know any of this hardware?
>>>       
>> The email messages are hidden in the depths of the linux-usb-devel 
>> archives.  Maybe you can find them by checking the Git history for 
>> drivers/usb/host/pci-quirks.c, finding the dates for patches that 
>> affected the handoff code, and then searching through the archives near 
>> those dates.
>>
>> IIRC the problems arose on some MIPS machines.  And I don't think the 
>> problem involved letting the firmware manage the USB controller; I 
>> think the problem came when the controller driver tried to do the 
>> handoff later on.
>>     
>
> It wasn't just MIPS.  IBM has a very popular blade system that has huge
> issues with this, and I think there are some other IBM systems based on
> the same BIOS that also do bad things if we don't grab the USB
> controller away from the BIOS as soon as possible (nasty interrupt and
> other messes happen...)
>
> thanks,
>
> greg k-h
>   
So we have hardware which has problems when we are not doing the
handoff, and hardware which has
problems when we are  doing the handoff...
What is the best way to solve the problem? Maybe a kernel parameter, a
config flag or an automatic
hardware dependent check of the system?
In fact it is hard to find a solution which works for both as long as
the hardware has this bugs.


Thanks


David Engraf

 

 
Netcom Sicherheitstechnik GmbH
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55120 Mainz
Tel: 	+49 6131 6305 0
Fax: 	+49 6131 6305 40
Email: 	david.engraf@netcom.eu

 
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Geschäftsführer: Peter Otto

Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[Alan Stern]

On Fri, 3 Aug 2007, David Engraf wrote:

> So we have hardware which has problems when we are not doing the
> handoff, and hardware which has
> problems when we are  doing the handoff...

What hardware has problems when we do the handoff?  Your system and 
mine experience a delay, but it doesn't break anything.

> What is the best way to solve the problem? Maybe a kernel parameter, a
> config flag or an automatic
> hardware dependent check of the system?
> In fact it is hard to find a solution which works for both as long as
> the hardware has this bugs.

If we really need it, I say we should use a Kconfig flag.

Alan Stern

Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[David Engraf]

You said your Intel board has also problems with the handoff.
Could you try the follwing patch, because the EHCI documentation
says that the OS must set the EHCI_USBLEGSUP_OS bit and then
wait until EHCI_USBLEGSUP_BIOS is cleared. The kernel never
uses the EHCI_USBLEGSUP_OS flag at the moment.
On my system there is no change, but maybe this patch works on
your system.

Thanks
David Engraf

linux-2.6.22.1

diff -puN drivers/usb/host/pci-quirks_orig.c drivers/usb/host/pci-quirks.c

--- drivers/usb/host/pci-quirks_orig.c    2007-07-10 20:56:30.000000000
+0200
+++ drivers/usb/host/pci-quirks.c    2007-08-07 10:38:33.000000000 +0200
@@ -268,6 +268,8 @@ static void __devinit quirk_usb_disable_
                  * handoff..
                  */
                 pci_write_config_byte(pdev, offset + 3, 1);
+
+                pci_write_config_byte(pdev, offset, cap |
EHCI_USBLEGSUP_OS);
             }
 
             /* if boot firmware now owns EHCI, spin till


Alan Stern schrieb:
> On Fri, 3 Aug 2007, David Engraf wrote:
>
>   
>> So we have hardware which has problems when we are not doing the
>> handoff, and hardware which has
>> problems when we are  doing the handoff...
>>     
>
> What hardware has problems when we do the handoff?  Your system and 
> mine experience a delay, but it doesn't break anything.
>
>   
>> What is the best way to solve the problem? Maybe a kernel parameter, a
>> config flag or an automatic
>> hardware dependent check of the system?
>> In fact it is hard to find a solution which works for both as long as
>> the hardware has this bugs.
>>     
>
> If we really need it, I say we should use a Kconfig flag.
>
> Alan Stern
>
>   

Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[Alan Stern]

On Tue, 7 Aug 2007, David Engraf wrote:

> You said your Intel board has also problems with the handoff.
> Could you try the follwing patch, because the EHCI documentation
> says that the OS must set the EHCI_USBLEGSUP_OS bit and then
> wait until EHCI_USBLEGSUP_BIOS is cleared. The kernel never
> uses the EHCI_USBLEGSUP_OS flag at the moment.

Yes it does.  Maybe not by that name, but it does set the bit.

> On my system there is no change, but maybe this patch works on
> your system.
> 
> Thanks
> David Engraf
> 
> linux-2.6.22.1
> 
> diff -puN drivers/usb/host/pci-quirks_orig.c drivers/usb/host/pci-quirks.c
> 
> --- drivers/usb/host/pci-quirks_orig.c    2007-07-10 20:56:30.000000000
> +0200
> +++ drivers/usb/host/pci-quirks.c    2007-08-07 10:38:33.000000000 +0200
> @@ -268,6 +268,8 @@ static void __devinit quirk_usb_disable_
>                   * handoff..
>                   */
>                  pci_write_config_byte(pdev, offset + 3, 1);
> +
> +                pci_write_config_byte(pdev, offset, cap |
> EHCI_USBLEGSUP_OS);

This patch is definitely wrong (besides being line-wrapped).  Note that
EHCI_USBLEGSUP_OS is equal to (1 << 24) -- it makes no sense to use it
as an argument for a byte-sized write.  Also note that the two 
low-order bytes in the USBLEGSUP register are read-only; you shouldn't 
try to write them at all.

It looks like you are simply attempting to do what the previous line of 
code already does.

Alan Stern

Re: [linux-usb-devel] [PATCH] USB BIOS early handoff only when the we the driver is configured

[Grant Grundler]

On Thu, Aug 02, 2007 at 09:43:29AM -0700, Greg KH wrote:
...
> It wasn't just MIPS.  IBM has a very popular blade system that has huge
> issues with this, and I think there are some other IBM systems based on
> the same BIOS that also do bad things if we don't grab the USB
> controller away from the BIOS as soon as possible (nasty interrupt and
> other messes happen...)

PA-RISC has the same problem with USB. We can't reprogram the IOMMU
windows at boot time unless the USB controller is forcefully stopped
from doing DMA. "BIOS" leaves the USB DMA enabled to avoid loosing
activity between polls for input.

PA-RISC solves this by calling back into the "BIOS" (aka PDC) to cleanly stop
all possible DMA devices. Other arches probably don't have this luxury.

grant