[PATCH] x86: early dump pci conf space

[PATCH] x86: early dump pci conf space

[Yinghai Lu]

so we can printout pci config before kernel touch it

also fix write_pci_config_byte with offset
and add write_pci_config_16

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

Index: linux-2.6/arch/x86/kernel/setup_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup_64.c
+++ linux-2.6/arch/x86/kernel/setup_64.c
@@ -350,6 +350,11 @@ void __init setup_arch(char **cmdline_p)
 
 	parse_early_param();
 
+#ifdef CONFIG_PCI
+	if (pci_early_dump_regs)
+		early_dump_pci_devices();
+#endif
+
 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
 	if (init_ohci1394_dma_early)
 		init_ohci1394_dma_on_all_controllers();
Index: linux-2.6/arch/x86/pci/common.c
===================================================================
--- linux-2.6.orig/arch/x86/pci/common.c
+++ linux-2.6/arch/x86/pci/common.c
@@ -20,6 +20,7 @@
 unsigned int pci_probe = PCI_PROBE_BIOS | PCI_PROBE_CONF1 | PCI_PROBE_CONF2 |
 				PCI_PROBE_MMCONF;
 
+unsigned int pci_early_dump_regs;
 static int pci_bf_sort;
 int pci_routeirq;
 int pcibios_last_bus = -1;
@@ -489,6 +490,9 @@ char * __devinit  pcibios_setup(char *st
 	} else if (!strcmp(str, "use_crs")) {
 		pci_probe |= PCI_USE__CRS;
 		return NULL;
+	} else if (!strcmp(str, "earlydump")) {
+		pci_early_dump_regs = 1;
+		return NULL;
 	} else if (!strcmp(str, "routeirq")) {
 		pci_routeirq = 1;
 		return NULL;
Index: linux-2.6/arch/x86/pci/early.c
===================================================================
--- linux-2.6.orig/arch/x86/pci/early.c
+++ linux-2.6/arch/x86/pci/early.c
@@ -49,7 +49,14 @@ void write_pci_config_byte(u8 bus, u8 sl
 {
 	PDprintk("%x writing to %x: %x\n", slot, offset, val);
 	outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
-	outb(val, 0xcfc);
+	outb(val, 0xcfc + (offset&3));
+}
+
+void write_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset, u16 val)
+{
+	PDprintk("%x writing to %x: %x\n", slot, offset, val);
+	outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
+	outw(val, 0xcfc + (offset&2));
 }
 
 int early_pci_allowed(void)
@@ -57,3 +64,54 @@ int early_pci_allowed(void)
 	return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
 			PCI_PROBE_CONF1;
 }
+
+void early_dump_pci_device(u8 bus, u8 slot, u8 func)
+{
+        int i;
+        int j;
+	u32 val;
+
+	printk("PCI: %02x:%02x:%02x", bus, slot, func);
+
+	for (i = 0; i < 256; i += 4) {
+		if (!(i & 0x0f))
+			printk("\n%04x:",i);
+
+		val = read_pci_config(bus, slot, func, i);
+		for (j = 0; j < 4; j++) {
+			printk(" %02x", val & 0xff);
+			val >>= 8;
+		}
+	}
+	printk("\n");
+}
+
+void early_dump_pci_devices(void)
+{
+	unsigned bus, slot, func;
+
+	if (!early_pci_allowed())
+		return;
+
+	for (bus = 0; bus < 256; bus++) {
+		for (slot = 0; slot < 32; slot++) {
+			for (func = 0; func < 8; func++) {
+				u32 class;
+				u8 type;
+				class = read_pci_config(bus, slot, func,
+							PCI_CLASS_REVISION);
+				if (class == 0xffffffff)
+					break;
+
+				early_dump_pci_device(bus, slot, func);
+
+				/* No multi-function device? */
+				type = read_pci_config_byte(bus, slot, func,
+							       PCI_HEADER_TYPE);
+				if (!(type & 0x80))
+					break;
+			}
+		}
+	}
+}
+
Index: linux-2.6/include/asm-x86/pci-direct.h
===================================================================
--- linux-2.6.orig/include/asm-x86/pci-direct.h
+++ linux-2.6/include/asm-x86/pci-direct.h
@@ -11,7 +11,11 @@ extern u8 read_pci_config_byte(u8 bus, u
 extern u16 read_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset);
 extern void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset, u32 val);
 extern void write_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset, u8 val);
+extern void write_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset, u16 val);
 
 extern int early_pci_allowed(void);
 
+extern unsigned int pci_early_dump_regs;
+extern void early_dump_pci_device(u8 bus, u8 slot, u8 func);
+extern void early_dump_pci_devices(void);
 #endif

Re: [PATCH] x86: early dump pci conf space

[Jesse Barnes]

On Wednesday, May 21, 2008 12:12 am Yinghai Lu wrote:
> so we can printout pci config before kernel touch it
>
> also fix write_pci_config_byte with offset
> and add write_pci_config_16

I like the idea.  Can you submit the write config byte fix separately?  I'll 
queue it up for 2.6.27 unless there are other comments.

Thanks,
Jesse

[PATCH] x86: early dump pci conf space v2

[Yinghai Lu]

so we can printout pci config before kernel touch it

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

Index: linux-2.6/arch/x86/kernel/setup_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup_64.c
+++ linux-2.6/arch/x86/kernel/setup_64.c
@@ -350,6 +350,11 @@ void __init setup_arch(char **cmdline_p)
 
 	parse_early_param();
 
+#ifdef CONFIG_PCI
+	if (pci_early_dump_regs)
+		early_dump_pci_devices();
+#endif
+
 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
 	if (init_ohci1394_dma_early)
 		init_ohci1394_dma_on_all_controllers();
Index: linux-2.6/arch/x86/pci/common.c
===================================================================
--- linux-2.6.orig/arch/x86/pci/common.c
+++ linux-2.6/arch/x86/pci/common.c
@@ -20,6 +20,7 @@
 unsigned int pci_probe = PCI_PROBE_BIOS | PCI_PROBE_CONF1 | PCI_PROBE_CONF2 |
 				PCI_PROBE_MMCONF;
 
+unsigned int pci_early_dump_regs;
 static int pci_bf_sort;
 int pci_routeirq;
 int pcibios_last_bus = -1;
@@ -489,6 +490,9 @@ char * __devinit  pcibios_setup(char *st
 	} else if (!strcmp(str, "use_crs")) {
 		pci_probe |= PCI_USE__CRS;
 		return NULL;
+	} else if (!strcmp(str, "earlydump")) {
+		pci_early_dump_regs = 1;
+		return NULL;
 	} else if (!strcmp(str, "routeirq")) {
 		pci_routeirq = 1;
 		return NULL;
Index: linux-2.6/arch/x86/pci/early.c
===================================================================
--- linux-2.6.orig/arch/x86/pci/early.c
+++ linux-2.6/arch/x86/pci/early.c
@@ -57,3 +57,54 @@ int early_pci_allowed(void)
 	return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
 			PCI_PROBE_CONF1;
 }
+
+void early_dump_pci_device(u8 bus, u8 slot, u8 func)
+{
+	int i;
+	int j;
+	u32 val;
+
+	printk("PCI: %02x:%02x:%02x", bus, slot, func);
+
+	for (i = 0; i < 256; i += 4) {
+		if (!(i & 0x0f))
+			printk("\n%04x:",i);
+
+		val = read_pci_config(bus, slot, func, i);
+		for (j = 0; j < 4; j++) {
+			printk(" %02x", val & 0xff);
+			val >>= 8;
+		}
+	}
+	printk("\n");
+}
+
+void early_dump_pci_devices(void)
+{
+	unsigned bus, slot, func;
+
+	if (!early_pci_allowed())
+		return;
+
+	for (bus = 0; bus < 256; bus++) {
+		for (slot = 0; slot < 32; slot++) {
+			for (func = 0; func < 8; func++) {
+				u32 class;
+				u8 type;
+				class = read_pci_config(bus, slot, func,
+							PCI_CLASS_REVISION);
+				if (class == 0xffffffff)
+					break;
+
+				early_dump_pci_device(bus, slot, func);
+
+				/* No multi-function device? */
+				type = read_pci_config_byte(bus, slot, func,
+							       PCI_HEADER_TYPE);
+				if (!(type & 0x80))
+					break;
+			}
+		}
+	}
+}
+
Index: linux-2.6/include/asm-x86/pci-direct.h
===================================================================
--- linux-2.6.orig/include/asm-x86/pci-direct.h
+++ linux-2.6/include/asm-x86/pci-direct.h
@@ -14,4 +14,7 @@ extern void write_pci_config_byte(u8 bus
 
 extern int early_pci_allowed(void);
 
+extern unsigned int pci_early_dump_regs;
+extern void early_dump_pci_device(u8 bus, u8 slot, u8 func);
+extern void early_dump_pci_devices(void);
 #endif

[PATCH] x86: write_pci_config_byte fix offset

[Yinghai Lu]

also add write_pci_config_16

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

Index: linux-2.6/arch/x86/pci/early.c
===================================================================
--- linux-2.6.orig/arch/x86/pci/early.c
+++ linux-2.6/arch/x86/pci/early.c
@@ -49,7 +49,14 @@ void write_pci_config_byte(u8 bus, u8 sl
 {
 	PDprintk("%x writing to %x: %x\n", slot, offset, val);
 	outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
-	outb(val, 0xcfc);
+	outb(val, 0xcfc + (offset&3));
+}
+
+void write_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset, u16 val)
+{
+	PDprintk("%x writing to %x: %x\n", slot, offset, val);
+	outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
+	outw(val, 0xcfc + (offset&2));
 }
 
 int early_pci_allowed(void)
Index: linux-2.6/include/asm-x86/pci-direct.h
===================================================================
--- linux-2.6.orig/include/asm-x86/pci-direct.h
+++ linux-2.6/include/asm-x86/pci-direct.h
@@ -11,6 +11,7 @@ extern u8 read_pci_config_byte(u8 bus, u
 extern u16 read_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset);
 extern void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset, u32 val);
 extern void write_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset, u8 val);
+extern void write_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset, u16 val);
 
 extern int early_pci_allowed(void);
 

Re: [PATCH] x86: write_pci_config_byte fix offset

[Jesse Barnes]

On Thursday, May 22, 2008 2:35 pm Yinghai Lu wrote:
> also add write_pci_config_16
>
> Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

Applied to linux-next, thanks Yinghai.

Jesse

Re: [PATCH] x86: early dump pci conf space v2

[Jesse Barnes]

On Thursday, May 22, 2008 2:35 pm Yinghai Lu wrote:
> so we can printout pci config before kernel touch it
>
> Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

Also applied to linux-next, this is a nice debugging feature.

Thanks,
Jesse

Re: [PATCH] x86: early dump pci conf space v2

[Grant Grundler]

On Thu, May 22, 2008 at 02:35:11PM -0700, Yinghai Lu wrote:
> 
> so we can printout pci config before kernel touch it
> 
> Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

Yinghai,
No offense, but my first thought was this is debug code that should be
maintained outside the kernel.org tree. It will rarely get used.
Just want people to think about this before saying "great, add it!"

(And this isn't a stab at Jesse since I think he's doing a better
job than I could. I saw his previous reply to this mail.)

Having debugged lots of PCI resource and config issues, I understand
why this is useful and do NOT object to it being included in the tree.

The boot option also needs to be added to Documentation/ .
At least if you want people to use it. :)
Perhaps Jesse can suggest a preferred location.


> Index: linux-2.6/arch/x86/kernel/setup_64.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/setup_64.c
> +++ linux-2.6/arch/x86/kernel/setup_64.c
> @@ -350,6 +350,11 @@ void __init setup_arch(char **cmdline_p)
>  
>  	parse_early_param();
>  
> +#ifdef CONFIG_PCI
> +	if (pci_early_dump_regs)
> +		early_dump_pci_devices();
> +#endif
> +
>  #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
>  	if (init_ohci1394_dma_early)
>  		init_ohci1394_dma_on_all_controllers();
> Index: linux-2.6/arch/x86/pci/common.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/pci/common.c
> +++ linux-2.6/arch/x86/pci/common.c
> @@ -20,6 +20,7 @@
>  unsigned int pci_probe = PCI_PROBE_BIOS | PCI_PROBE_CONF1 | PCI_PROBE_CONF2 |
>  				PCI_PROBE_MMCONF;
>  
> +unsigned int pci_early_dump_regs;
>  static int pci_bf_sort;
>  int pci_routeirq;
>  int pcibios_last_bus = -1;
> @@ -489,6 +490,9 @@ char * __devinit  pcibios_setup(char *st
>  	} else if (!strcmp(str, "use_crs")) {
>  		pci_probe |= PCI_USE__CRS;
>  		return NULL;
> +	} else if (!strcmp(str, "earlydump")) {

Please call this "pci_early_dump" (I prefer with underscores but don't care).
Don't want it confused with kernel dumps (LKCD) or any other
general debugging tools.

thanks,
grant

> +		pci_early_dump_regs = 1;
> +		return NULL;
>  	} else if (!strcmp(str, "routeirq")) {
>  		pci_routeirq = 1;
>  		return NULL;
> Index: linux-2.6/arch/x86/pci/early.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/pci/early.c
> +++ linux-2.6/arch/x86/pci/early.c
> @@ -57,3 +57,54 @@ int early_pci_allowed(void)
>  	return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
>  			PCI_PROBE_CONF1;
>  }
> +
> +void early_dump_pci_device(u8 bus, u8 slot, u8 func)
> +{
> +	int i;
> +	int j;
> +	u32 val;
> +
> +	printk("PCI: %02x:%02x:%02x", bus, slot, func);
> +
> +	for (i = 0; i < 256; i += 4) {
> +		if (!(i & 0x0f))
> +			printk("\n%04x:",i);
> +
> +		val = read_pci_config(bus, slot, func, i);
> +		for (j = 0; j < 4; j++) {
> +			printk(" %02x", val & 0xff);
> +			val >>= 8;
> +		}
> +	}
> +	printk("\n");
> +}
> +
> +void early_dump_pci_devices(void)
> +{
> +	unsigned bus, slot, func;
> +
> +	if (!early_pci_allowed())
> +		return;
> +
> +	for (bus = 0; bus < 256; bus++) {
> +		for (slot = 0; slot < 32; slot++) {
> +			for (func = 0; func < 8; func++) {
> +				u32 class;
> +				u8 type;
> +				class = read_pci_config(bus, slot, func,
> +							PCI_CLASS_REVISION);
> +				if (class == 0xffffffff)
> +					break;
> +
> +				early_dump_pci_device(bus, slot, func);
> +
> +				/* No multi-function device? */
> +				type = read_pci_config_byte(bus, slot, func,
> +							       PCI_HEADER_TYPE);
> +				if (!(type & 0x80))
> +					break;
> +			}
> +		}
> +	}
> +}
> +
> Index: linux-2.6/include/asm-x86/pci-direct.h
> ===================================================================
> --- linux-2.6.orig/include/asm-x86/pci-direct.h
> +++ linux-2.6/include/asm-x86/pci-direct.h
> @@ -14,4 +14,7 @@ extern void write_pci_config_byte(u8 bus
>  
>  extern int early_pci_allowed(void);
>  
> +extern unsigned int pci_early_dump_regs;
> +extern void early_dump_pci_device(u8 bus, u8 slot, u8 func);
> +extern void early_dump_pci_devices(void);
>  #endif
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] x86: early dump pci conf space v2

[Yinghai Lu]

On Thu, May 22, 2008 at 10:38 PM, Grant Grundler
<grundler@parisc-linux.org> wrote:
> On Thu, May 22, 2008 at 02:35:11PM -0700, Yinghai Lu wrote:
>>
>> so we can printout pci config before kernel touch it
>>
>> Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
>
> Yinghai,
> No offense, but my first thought was this is debug code that should be
> maintained outside the kernel.org tree. It will rarely get used.
> Just want people to think about this before saying "great, add it!"
>
> (And this isn't a stab at Jesse since I think he's doing a better
> job than I could. I saw his previous reply to this mail.)
>
> Having debugged lots of PCI resource and config issues, I understand
> why this is useful and do NOT object to it being included in the tree.

could print out the setting from buggy BIOS, or first kernel.
and don't need the reporter apply debug patch again...

>
> The boot option also needs to be added to Documentation/ .
> At least if you want people to use it. :)
> Perhaps Jesse can suggest a preferred location.

we could add it.
..
>
> Please call this "pci_early_dump" (I prefer with underscores but don't care).
> Don't want it confused with kernel dumps (LKCD) or any other
> general debugging tools.

so you want pci_early_dump instead of pci=earlydump?
or pci=early_dump?

YH

Re: [PATCH] x86: early dump pci conf space v2

[Jesse Barnes]

On Thursday, May 22, 2008 10:38 pm Grant Grundler wrote:
> On Thu, May 22, 2008 at 02:35:11PM -0700, Yinghai Lu wrote:
> > so we can printout pci config before kernel touch it
> >
> > Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
>
> Yinghai,
> No offense, but my first thought was this is debug code that should be
> maintained outside the kernel.org tree. It will rarely get used.
> Just want people to think about this before saying "great, add it!"
>
> (And this isn't a stab at Jesse since I think he's doing a better
> job than I could. I saw his previous reply to this mail.)
>
> Having debugged lots of PCI resource and config issues, I understand
> why this is useful and do NOT object to it being included in the tree.

Yeah I thought about this too, but:
  1) it's definitely useful for debugging PCI issues, and much easier for 
everyone if it's in-tree
  2) it only bloats x86 kernels ;)

Documentation is definitely needed though, thanks for catching that.

Thanks,
Jesse

Re: [PATCH] x86: early dump pci conf space v2

[Jesse Barnes]

On Thursday, May 22, 2008 11:38 pm Yinghai Lu wrote:
> > Please call this "pci_early_dump" (I prefer with underscores but don't
> > care). Don't want it confused with kernel dumps (LKCD) or any other
> > general debugging tools.
>
> so you want pci_early_dump instead of pci=earlydump?
> or pci=early_dump?

Or early_config_dump, I don't have a strong preference (but Grant's right that 
a pci_ prefix should be on there somewhere, either pci= or pci_).

Can you send me a replacement for the patch that added it once you come up 
with something?

Thanks,
Jesse

[PATCH] x86: early dump pci conf space v3

[Yinghai Lu]

so we can printout pci config before kernel touch it
v3: change to pci=early_config_dump

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

Index: linux-2.6/arch/x86/kernel/setup_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup_64.c
+++ linux-2.6/arch/x86/kernel/setup_64.c
@@ -350,6 +350,11 @@ void __init setup_arch(char **cmdline_p)
 
 	parse_early_param();
 
+#ifdef CONFIG_PCI
+	if (pci_early_config_dump)
+		early_dump_pci_devices();
+#endif
+
 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
 	if (init_ohci1394_dma_early)
 		init_ohci1394_dma_on_all_controllers();
Index: linux-2.6/arch/x86/pci/common.c
===================================================================
--- linux-2.6.orig/arch/x86/pci/common.c
+++ linux-2.6/arch/x86/pci/common.c
@@ -20,6 +20,7 @@
 unsigned int pci_probe = PCI_PROBE_BIOS | PCI_PROBE_CONF1 | PCI_PROBE_CONF2 |
 				PCI_PROBE_MMCONF;
 
+unsigned int pci_early_config_dump;
 static int pci_bf_sort;
 int pci_routeirq;
 int pcibios_last_bus = -1;
@@ -489,6 +490,9 @@ char * __devinit  pcibios_setup(char *st
 	} else if (!strcmp(str, "use_crs")) {
 		pci_probe |= PCI_USE__CRS;
 		return NULL;
+	} else if (!strcmp(str, "early_config_dump")) {
+		pci_early_config_dump = 1;
+		return NULL;
 	} else if (!strcmp(str, "routeirq")) {
 		pci_routeirq = 1;
 		return NULL;
Index: linux-2.6/arch/x86/pci/early.c
===================================================================
--- linux-2.6.orig/arch/x86/pci/early.c
+++ linux-2.6/arch/x86/pci/early.c
@@ -57,3 +57,57 @@ int early_pci_allowed(void)
 	return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
 			PCI_PROBE_CONF1;
 }
+
+void early_dump_pci_device(u8 bus, u8 slot, u8 func)
+{
+	int i;
+	int j;
+	u32 val;
+
+	if (!early_pci_allowed())
+		return;
+
+	printk("PCI: %02x:%02x:%02x", bus, slot, func);
+
+	for (i = 0; i < 256; i += 4) {
+		if (!(i & 0x0f))
+			printk("\n%04x:",i);
+
+		val = read_pci_config(bus, slot, func, i);
+		for (j = 0; j < 4; j++) {
+			printk(" %02x", val & 0xff);
+			val >>= 8;
+		}
+	}
+	printk("\n");
+}
+
+void early_dump_pci_devices(void)
+{
+	unsigned bus, slot, func;
+
+	if (!early_pci_allowed())
+		return;
+
+	for (bus = 0; bus < 256; bus++) {
+		for (slot = 0; slot < 32; slot++) {
+			for (func = 0; func < 8; func++) {
+				u32 class;
+				u8 type;
+				class = read_pci_config(bus, slot, func,
+							PCI_CLASS_REVISION);
+				if (class == 0xffffffff)
+					break;
+
+				early_dump_pci_device(bus, slot, func);
+
+				/* No multi-function device? */
+				type = read_pci_config_byte(bus, slot, func,
+							       PCI_HEADER_TYPE);
+				if (!(type & 0x80))
+					break;
+			}
+		}
+	}
+}
+
Index: linux-2.6/include/asm-x86/pci-direct.h
===================================================================
--- linux-2.6.orig/include/asm-x86/pci-direct.h
+++ linux-2.6/include/asm-x86/pci-direct.h
@@ -14,4 +14,7 @@ extern void write_pci_config_byte(u8 bus
 
 extern int early_pci_allowed(void);
 
+extern unsigned int pci_early_config_dump;
+extern void early_dump_pci_device(u8 bus, u8 slot, u8 func);
+extern void early_dump_pci_devices(void);
 #endif
Index: linux-2.6/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.orig/Documentation/kernel-parameters.txt
+++ linux-2.6/Documentation/kernel-parameters.txt
@@ -1570,6 +1570,8 @@ and is between 256 and 4096 characters. 
 		cbmemsize=nn[KMG]	The fixed amount of bus space which is
 				reserved for the CardBus bridge's memory
 				window. The default value is 64 megabytes.
+		early_config_dump	[X86] print out pci config space
+				registers early before kernel touch any
 
 	pcmv=		[HW,PCMCIA] BadgePAD 4
 
Index: linux-2.6/arch/x86/kernel/setup_32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup_32.c
+++ linux-2.6/arch/x86/kernel/setup_32.c
@@ -46,6 +46,7 @@
 #include <linux/dmi.h>
 #include <linux/pfn.h>
 #include <linux/pci.h>
+#include <asm/pci-direct.h>
 #include <linux/init_ohci1394_dma.h>
 #include <linux/kvm_para.h>
 
@@ -692,6 +693,11 @@ void __init setup_arch(char **cmdline_p)
 
 	parse_early_param();
 
+#ifdef CONFIG_PCI
+	if (pci_early_config_dump)
+		early_dump_pci_devices();
+#endif
+
 	finish_e820_parsing();
 
 	strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);

Re: [PATCH] x86: early dump pci conf space v2

[Grant Grundler]

On Thu, May 22, 2008 at 11:38:24PM -0700, Yinghai Lu wrote:
...
> > Having debugged lots of PCI resource and config issues, I understand
> > why this is useful and do NOT object to it being included in the tree.
> 
> could print out the setting from buggy BIOS, or first kernel.
> and don't need the reporter apply debug patch again...

Yes, I understood. Here are some more details on why my first
reaction was negative:
o Most of the time the system can boot anyway and we get lspci -v output,
  /proc/iomem, etc. If that's not true, then other parts of the kernel
  need to be more robust (e.g. drivers crashing because resources aren't
  assigned.

o Bringing up linux on a new platform is NOT something we've generally
  had to do via email. Usually someone with kernel/IO experience is
  involved and can build new kernels.

> > At least if you want people to use it. :)
> > Perhaps Jesse can suggest a preferred location.
> 
> we could add it.
> ..
> >
> > Please call this "pci_early_dump" (I prefer with underscores but don't care).
> > Don't want it confused with kernel dumps (LKCD) or any other
> > general debugging tools.
> 
> so you want pci_early_dump instead of pci=earlydump?
> or pci=early_dump?

Sorry, I misread the patch.
I was thinking of "pci_early_dump" as a seperate option but
either "pci=" option is fine.

thanks,
grant

Re: [PATCH] x86: early dump pci conf space v3

[Grant Grundler]

On Fri, May 23, 2008 at 12:48:54PM -0700, Yinghai Lu wrote:
> 
> so we can printout pci config before kernel touch it
> v3: change to pci=early_config_dump
...
> Index: linux-2.6/Documentation/kernel-parameters.txt
> ===================================================================
> --- linux-2.6.orig/Documentation/kernel-parameters.txt
> +++ linux-2.6/Documentation/kernel-parameters.txt
> @@ -1570,6 +1570,8 @@ and is between 256 and 4096 characters. 
>  		cbmemsize=nn[KMG]	The fixed amount of bus space which is
>  				reserved for the CardBus bridge's memory
>  				window. The default value is 64 megabytes.
> +		early_config_dump	[X86] print out pci config space
> +				registers early before kernel touch any

A bit of wordsmithing here:

		early_config_dump	[X86] print out pci config space
					registers before the kernel touches
					any PCI resources. This can help
					determine what PCI quirks need to
					do to compensate for broken BIOS.

Rest of the patch:
Acked-by: Grant Grundler <grundler@parisc-linux.org>

thanks,
grant