[PATCH] quiet MMCONFIG related printks

[PATCH] quiet MMCONFIG related printks

[Jesse Barnes]

Using MMCONFIG for PCI config space access is simply an optimization, not
a requirement.  Therefore, when it can't be used, there's no need for
KERN_ERR level message.  This patch makes the message a KERN_INFO instead
to reduce some of the noise in a kernel boot with the 'quiet' option.
(Note that this has no effect on a normal boot, which is ridiculously
verbose these days.)

Signed-off-by:  Jesse Barnes <jbarnes@virtuousgeek.org>

Thanks,
Jesse

diff --git a/arch/i386/pci/mmconfig.c b/arch/i386/pci/mmconfig.c
index e2616a2..b95e7f3 100644
--- a/arch/i386/pci/mmconfig.c
+++ b/arch/i386/pci/mmconfig.c
@@ -210,9 +210,9 @@ void __init pci_mmcfg_init(int type)
 	if (type == 1 && !e820_all_mapped(pci_mmcfg_config[0].base_address,
 			pci_mmcfg_config[0].base_address + MMCONFIG_APER_MIN,
 			E820_RESERVED)) {
-		printk(KERN_ERR "PCI: BIOS Bug: MCFG area at %x is not E820-reserved\n",
+		printk(KERN_INFO "PCI: BIOS Bug: MCFG area at %x is not E820-reserved\n",
 				pci_mmcfg_config[0].base_address);
-		printk(KERN_ERR "PCI: Not using MMCONFIG.\n");
+		printk(KERN_INFO "PCI: Not using MMCONFIG.\n");
 		return;
 	}
 

Re: [PATCH] quiet MMCONFIG related printks

[Alan]

On Mon, 1 Jan 2007 21:01:38 -0800
Jesse Barnes <jbarnes@virtuousgeek.org> wrote:

> Using MMCONFIG for PCI config space access is simply an optimization, not
> a requirement.  Therefore, when it can't be used, there's no need for

Some hardware reqires MCFG. In addition this is an error, a real error on
the vendors part or ours and could indicate there are many other BIOS
problems outstanding.

We shouldn't keep quiet about serious errors in tables, we need people to
know and be able to take appropriate action (eg new BIOSen, refusing
certifications etc).


NAK

Re: [PATCH] quiet MMCONFIG related printks

[Jesse Barnes]

On Tuesday, January 2, 2007 2:36 am, Alan wrote:
> On Mon, 1 Jan 2007 21:01:38 -0800
>
> Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
> > Using MMCONFIG for PCI config space access is simply an
> > optimization, not a requirement.  Therefore, when it can't be used,
> > there's no need for
>
> Some hardware reqires MCFG. In addition this is an error, a real
> error on the vendors part or ours and could indicate there are many
> other BIOS problems outstanding.

Ok, I was mistaken then.  However, I see this on several boxes, and the 
broken BIOSen out in the wild are unlikely to be fixed.  Maybe this 
should really be a KERN_WARNING instead since it may indicate that some 
devices will fail to work?

> We shouldn't keep quiet about serious errors in tables, we need
> people to know and be able to take appropriate action (eg new BIOSen,
> refusing certifications etc).

Ok.

Jesse

Re: [PATCH] quiet MMCONFIG related printks

[Arjan van de Ven]

On Tue, 2007-01-02 at 10:36 +0000, Alan wrote:
> On Mon, 1 Jan 2007 21:01:38 -0800
> Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
> 
> > Using MMCONFIG for PCI config space access is simply an optimization, not
> > a requirement.  Therefore, when it can't be used, there's no need for
> 
> Some hardware reqires MCFG. In addition this is an error, a real error on
> the vendors part or ours and could indicate there are many other BIOS
> problems outstanding.
> 
> We shouldn't keep quiet about serious errors in tables, we need people to
> know and be able to take appropriate action (eg new BIOSen, refusing
> certifications etc).

to some degree that is what the firmware kit is for ;)

-- 
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org

Re: [PATCH] quiet MMCONFIG related printks

[Arjan van de Ven]

On Mon, 2007-01-01 at 21:01 -0800, Jesse Barnes wrote:
> Using MMCONFIG for PCI config space access is simply an optimization, not
> a requirement.  Therefore, when it can't be used, there's no need for
> KERN_ERR level message.  This patch makes the message a KERN_INFO instead
> to reduce some of the noise in a kernel boot with the 'quiet' option.
> (Note that this has no effect on a normal boot, which is ridiculously
> verbose these days.)


this is wrong, please leave this loud complaint in...

-- 
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org

Re: [PATCH] quiet MMCONFIG related printks

[Jesse Barnes]

On Wednesday, January 3, 2007 5:53 am, Arjan van de Ven wrote:
> On Mon, 2007-01-01 at 21:01 -0800, Jesse Barnes wrote:
> > Using MMCONFIG for PCI config space access is simply an
> > optimization, not a requirement.  Therefore, when it can't be used,
> > there's no need for KERN_ERR level message.  This patch makes the
> > message a KERN_INFO instead to reduce some of the noise in a kernel
> > boot with the 'quiet' option. (Note that this has no effect on a
> > normal boot, which is ridiculously verbose these days.)
>
> this is wrong, please leave this loud complaint in...

So the issues as I understand them:
  o some BIOSes are broken and don't properly map MCFG space (though
    according to Petr V. reserving MCFG space in e820 is optional, so
    the test may be slightly wrong as-is)
  o MCFG space is required for (many) PCIe devices (any regular PCI
    devices?)
  o often, there's nothing the user can do to address the points above

So where does that leave us?  I've got what I consider to be a stupid 
error message in my log.  My system behavior isn't affected in any way 
(at least that I can tell), yet I get a loud complaint at boot time.

I guess I just have to live with it?

Thanks,
Jesse

Re: [PATCH] quiet MMCONFIG related printks

[Arjan van de Ven]

On Wed, 2007-01-03 at 08:49 -0800, Jesse Barnes wrote:
> On Wednesday, January 3, 2007 5:53 am, Arjan van de Ven wrote:
> > On Mon, 2007-01-01 at 21:01 -0800, Jesse Barnes wrote:
> > > Using MMCONFIG for PCI config space access is simply an
> > > optimization, not a requirement.  Therefore, when it can't be used,
> > > there's no need for KERN_ERR level message.  This patch makes the
> > > message a KERN_INFO instead to reduce some of the noise in a kernel
> > > boot with the 'quiet' option. (Note that this has no effect on a
> > > normal boot, which is ridiculously verbose these days.)
> >
> > this is wrong, please leave this loud complaint in...
> 
> So the issues as I understand them:
>   o some BIOSes are broken and don't properly map MCFG space (though
>     according to Petr V. reserving MCFG space in e820 is optional, so
>     the test may be slightly wrong as-is)

it's optional but it's the best test we have for "is the bios total
crap" ;(

>   o MCFG space is required for (many) PCIe devices (any regular PCI
>     devices?)

it's not required for *many* (it can't be, windows XP doesn't use MCFG),
but it's required for some of the advanced PCI-E features

>   o often, there's nothing the user can do to address the points above

other than complain to the vendor.

> 
> So where does that leave us?  I've got what I consider to be a stupid 
> error message in my log.

contact your bios vendor.

>   My system behavior isn't affected in any way 
> (at least that I can tell), yet I get a loud complaint at boot time.
> 
> I guess I just have to live with it?

We really really should complain about bios issues. If only to make sure
vendors who do pay attention to linux have a chance of finding and
fixing them (and via the firmware kit, several big vendors pay attention
early on nowadays)

-- 
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org

Re: [PATCH] quiet MMCONFIG related printks

[Stephen Clark]

Arjan van de Ven wrote:

>On Wed, 2007-01-03 at 08:49 -0800, Jesse Barnes wrote:
>  
>
>>On Wednesday, January 3, 2007 5:53 am, Arjan van de Ven wrote:
>>    
>>
>>>On Mon, 2007-01-01 at 21:01 -0800, Jesse Barnes wrote:
>>>      
>>>
>>>>Using MMCONFIG for PCI config space access is simply an
>>>>optimization, not a requirement.  Therefore, when it can't be used,
>>>>there's no need for KERN_ERR level message.  This patch makes the
>>>>message a KERN_INFO instead to reduce some of the noise in a kernel
>>>>boot with the 'quiet' option. (Note that this has no effect on a
>>>>normal boot, which is ridiculously verbose these days.)
>>>>        
>>>>
>>>this is wrong, please leave this loud complaint in...
>>>      
>>>
>>So the issues as I understand them:
>>  o some BIOSes are broken and don't properly map MCFG space (though
>>    according to Petr V. reserving MCFG space in e820 is optional, so
>>    the test may be slightly wrong as-is)
>>    
>>
>
>it's optional but it's the best test we have for "is the bios total
>crap" ;(
>
>  
>
>>  o MCFG space is required for (many) PCIe devices (any regular PCI
>>    devices?)
>>    
>>
>
>it's not required for *many* (it can't be, windows XP doesn't use MCFG),
>but it's required for some of the advanced PCI-E features
>
>  
>
>>  o often, there's nothing the user can do to address the points above
>>    
>>
>
>other than complain to the vendor.
>
>  
>
>>So where does that leave us?  I've got what I consider to be a stupid 
>>error message in my log.
>>    
>>
>
>contact your bios vendor.
>
>  
>
>>  My system behavior isn't affected in any way 
>>(at least that I can tell), yet I get a loud complaint at boot time.
>>
>>I guess I just have to live with it?
>>    
>>
>
>We really really should complain about bios issues. If only to make sure
>vendors who do pay attention to linux have a chance of finding and
>fixing them (and via the firmware kit, several big vendors pay attention
>early on nowadays)
>
>  
>
Hi Arjan,

Do you have a list of E-Mail addresses for the people we should be 
complaining to. I have an
Asus VBI laptop that spews all kinds of error messages when I boot the 
firmware test kit cd, but
I have no idea who to complain to about this, ASUS? Intel? Heck Intel 
puts out the test kit, if they
are going to say it is VBI why don't the make the vendors do the bios 
correctly?

Regards,
Steve

-- 

"They that give up essential liberty to obtain temporary safety, 
deserve neither liberty nor safety."  (Ben Franklin)

"The course of history shows that as a government grows, liberty 
decreases."  (Thomas Jefferson)

Re: [PATCH] quiet MMCONFIG related printks

[Jesse Barnes]

On Wednesday, January 3, 2007 5:53 am, Arjan van de Ven wrote:
> On Mon, 2007-01-01 at 21:01 -0800, Jesse Barnes wrote:
> > Using MMCONFIG for PCI config space access is simply an
> > optimization, not a requirement.  Therefore, when it can't be used,
> > there's no need for KERN_ERR level message.  This patch makes the
> > message a KERN_INFO instead to reduce some of the noise in a kernel
> > boot with the 'quiet' option. (Note that this has no effect on a
> > normal boot, which is ridiculously verbose these days.)
>
> this is wrong, please leave this loud complaint in...

Or maybe the test is just wrong.  I'll try out the PCI MMConfig 
per-chipset patches to see if they work.  That seems like a better long 
term solution anyway.

Thanks,
Jesse