[PATCH] powerpc: Fix ide-pmac sysfs entry

[PATCH] powerpc: Fix ide-pmac sysfs entry

[Benjamin Herrenschmidt]

It looks like the generic ide code now wants ide_init_hwif_ports() to
set the parent struct device into the ide_hw structure (new field ?).
Without this, the mac ide code can cause the ide probing code to explode
in flames in sysfs registration due to what looks like a stale pointer
in there (happens when removing/re-inserting one of the hotswap media
bays on some laptops).

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

Andew: That's a 2.6.17 candidate 

Index: linux-work/drivers/ide/ppc/pmac.c
===================================================================
--- linux-work.orig/drivers/ide/ppc/pmac.c	2006-04-19 15:04:47.000000000 +1000
+++ linux-work/drivers/ide/ppc/pmac.c	2006-05-15 16:43:20.000000000 +1000
@@ -553,6 +553,8 @@
 
 	if (irq != NULL)
 		*irq = pmac_ide[ix].irq;
+
+	hw->dev = &pmac_ide[ix].mdev->ofdev.dev;
 }
 
 #define PMAC_IDE_REG(x) ((void __iomem *)(IDE_DATA_REG+(x)))
 

Re: [PATCH] powerpc: Fix ide-pmac sysfs entry

[Andrew Morton]

Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
>
> It looks like the generic ide code now wants ide_init_hwif_ports() to
> set the parent struct device into the ide_hw structure (new field ?).
> Without this, the mac ide code can cause the ide probing code to explode
> in flames in sysfs registration due to what looks like a stale pointer
> in there (happens when removing/re-inserting one of the hotswap media
> bays on some laptops).
> 

You don't sound very confident.

> ---
> 
> Andew: That's a 2.6.17 candidate 
> 
> Index: linux-work/drivers/ide/ppc/pmac.c
> ===================================================================
> --- linux-work.orig/drivers/ide/ppc/pmac.c	2006-04-19 15:04:47.000000000 +1000
> +++ linux-work/drivers/ide/ppc/pmac.c	2006-05-15 16:43:20.000000000 +1000
> @@ -553,6 +553,8 @@
>  
>  	if (irq != NULL)
>  		*irq = pmac_ide[ix].irq;
> +
> +	hw->dev = &pmac_ide[ix].mdev->ofdev.dev;
>  }
>  
>  #define PMAC_IDE_REG(x) ((void __iomem *)(IDE_DATA_REG+(x)))
>  

afaict things went bad in October last year.  hw_regs_t.dev was added here:

http://www.kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=26a940e21752e0de8f068f77dad606a7d1986937

but that only converted one driver to initialse ->dev.

How come things didn't break then?  Did some later change cause the
problems?

Re: [PATCH] powerpc: Fix ide-pmac sysfs entry

[Benjamin Herrenschmidt]

On Mon, 2006-05-15 at 00:08 -0700, Andrew Morton wrote:
> Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> >
> > It looks like the generic ide code now wants ide_init_hwif_ports() to
> > set the parent struct device into the ide_hw structure (new field ?).
> > Without this, the mac ide code can cause the ide probing code to explode
> > in flames in sysfs registration due to what looks like a stale pointer
> > in there (happens when removing/re-inserting one of the hotswap media
> > bays on some laptops).
> > 
> 
> You don't sound very confident.

Well, the problem is fixed with my change, I'd like to have Bart
confirmation that's its the right approach. It looks like it is but that
code is fairly intricated :)

> afaict things went bad in October last year.  hw_regs_t.dev was added here:
> 
> http://www.kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=26a940e21752e0de8f068f77dad606a7d1986937
> 
> but that only converted one driver to initialse ->dev.
> 
> How come things didn't break then?  Did some later change cause the
> problems?

Well, for one, very few drivers cause ide_unregister nor rely on those
old mecanism... it seems that the way I initialize things at boot works
fine, it's when I unregister/re-register via the hotswap bay that things
go bunk.

It's possible that it got broken back then and not noticed since ... or
another change actually made _use_ of that field... not sure, Bart might
confirm. The Mac laptops with those hotswap bays are fairly old and I
haven't tested for some time. I just did after getting user reports, and
users of old machines like that tend to use stable distro kernels which
tend to be fairly old...

Ben.
 

Re: [PATCH] powerpc: Fix ide-pmac sysfs entry

[Gabriel Paubert]

On Mon, May 15, 2006 at 05:23:50PM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2006-05-15 at 00:08 -0700, Andrew Morton wrote:
> > Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> > >
> > > It looks like the generic ide code now wants ide_init_hwif_ports() to
> > > set the parent struct device into the ide_hw structure (new field ?).
> > > Without this, the mac ide code can cause the ide probing code to explode
> > > in flames in sysfs registration due to what looks like a stale pointer
> > > in there (happens when removing/re-inserting one of the hotswap media
> > > bays on some laptops).
> > > 
> > 
> > You don't sound very confident.
> 
> Well, the problem is fixed with my change, I'd like to have Bart
> confirmation that's its the right approach. It looks like it is but that
> code is fairly intricated :)
> 
> > afaict things went bad in October last year.  hw_regs_t.dev was added here:
> > 
> > http://www.kernel.org/git/gitweb.cgi?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=26a940e21752e0de8f068f77dad606a7d1986937
> > 
> > but that only converted one driver to initialse ->dev.
> > 
> > How come things didn't break then?  Did some later change cause the
> > problems?
> 
> Well, for one, very few drivers cause ide_unregister nor rely on those
> old mecanism... it seems that the way I initialize things at boot works
> fine, it's when I unregister/re-register via the hotswap bay that things
> go bunk.
> 
> It's possible that it got broken back then and not noticed since ... or
> another change actually made _use_ of that field... not sure, Bart might
> confirm. The Mac laptops with those hotswap bays are fairly old and I
> haven't tested for some time. I just did after getting user reports, and
> users of old machines like that tend to use stable distro kernels which
> tend to be fairly old...

Actually I have one of these, and regularly use it and update 
the kernel to the latest git once or twice per month, but I 
typically have two batteries and have not swapped in the 
media bay under Linux for a long time.

If you are interested, I could test the patch when I find 
some time (not today: my 8 year old son went to the hospital
for an emergency last Thursday, he is cured now and should 
come out today).

	Regards,
	Gabriel

Re: [PATCH] powerpc: Fix ide-pmac sysfs entry

[Benjamin Herrenschmidt]

> Actually I have one of these, and regularly use it and update 
> the kernel to the latest git once or twice per month, but I 
> typically have two batteries and have not swapped in the 
> media bay under Linux for a long time.
> 
> If you are interested, I could test the patch when I find 
> some time (not today: my 8 year old son went to the hospital
> for an emergency last Thursday, he is cured now and should 
> come out today).

Any test is welcome, glad to know your son is well !

Cheers,
Ben.

Re: [PATCH] powerpc: Fix ide-pmac sysfs entry

[Gabriel Paubert]

On Mon, May 15, 2006 at 06:52:36PM +1000, Benjamin Herrenschmidt wrote:
> 
> > Actually I have one of these, and regularly use it and update 
> > the kernel to the latest git once or twice per month, but I 
> > typically have two batteries and have not swapped in the 
> > media bay under Linux for a long time.
> > 
> > If you are interested, I could test the patch when I find 
> > some time (not today: my 8 year old son went to the hospital
> > for an emergency last Thursday, he is cured now and should 
> > come out today).
> 
> Any test is welcome, glad to know your son is well !

The one liner works here, I can no more solidly hang
the machine. There is still a bunch of error messages
on drive removal though:

mediabay0: switching to 7
mediabay0: powering down
media bay 0 is empty
Unregistering mb 0 ide, index:2
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: DMA disabled
hde: ATAPI reset complete
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: ATAPI reset complete
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: ATAPI reset complete
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
hde: ATAPI reset complete
hde: status error: status=0x00 { }
ide: failed opcode was: unknown
mediabay0: end of power down

On insertion there are also a few messages
but they seem normal:

mediabay0: switching to 3
mediabay0: powering up
mediabay0: enabling (kind:3)
mediabay0: waiting reset (kind:3)
mediabay0: waiting IDE reset (kind:3)
mediabay0: waiting IDE ready (kind:3)
mediabay 0, registering IDE...
Probing IDE interface ide2...
hde: LG DVD-ROM DRN-8080B, ATAPI CD/DVD-ROM drive
hde: Enabling MultiWord DMA 2
ide2 at 0xf1022000-0xf1022007,0xf1022160 on irq 20
hde: ATAPI 24X DVD-ROM drive, 512kB Cache, DMA
media-bay 0 is ide2
mediabay 0 IDE ready

	Regards,
	Gabriel

Re: [PATCH] powerpc: Fix ide-pmac sysfs entry

[Benjamin Herrenschmidt]

On Sun, 2006-05-21 at 23:30 +0200, Gabriel Paubert wrote:
> On Mon, May 15, 2006 at 06:52:36PM +1000, Benjamin Herrenschmidt wrote:
> > 
> > > Actually I have one of these, and regularly use it and update 
> > > the kernel to the latest git once or twice per month, but I 
> > > typically have two batteries and have not swapped in the 
> > > media bay under Linux for a long time.
> > > 
> > > If you are interested, I could test the patch when I find 
> > > some time (not today: my 8 year old son went to the hospital
> > > for an emergency last Thursday, he is cured now and should 
> > > come out today).
> > 
> > Any test is welcome, glad to know your son is well !
> 
> The one liner works here, I can no more solidly hang
> the machine. There is still a bunch of error messages
> on drive removal though:

Yes, I noticed those. Looks like the IDE driver is trying to much around
with the drive when unregistered. In our case, it's not a very good idea
as we unregister it after we detect it's been physically removed :)
Seems harmless so far though.

Ben.

> mediabay0: switching to 7
> mediabay0: powering down
> media bay 0 is empty
> Unregistering mb 0 ide, index:2
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: DMA disabled
> hde: ATAPI reset complete
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: ATAPI reset complete
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: ATAPI reset complete
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> hde: ATAPI reset complete
> hde: status error: status=0x00 { }
> ide: failed opcode was: unknown
> mediabay0: end of power down
> 
> On insertion there are also a few messages
> but they seem normal:
> 
> mediabay0: switching to 3
> mediabay0: powering up
> mediabay0: enabling (kind:3)
> mediabay0: waiting reset (kind:3)
> mediabay0: waiting IDE reset (kind:3)
> mediabay0: waiting IDE ready (kind:3)
> mediabay 0, registering IDE...
> Probing IDE interface ide2...
> hde: LG DVD-ROM DRN-8080B, ATAPI CD/DVD-ROM drive
> hde: Enabling MultiWord DMA 2
> ide2 at 0xf1022000-0xf1022007,0xf1022160 on irq 20
> hde: ATAPI 24X DVD-ROM drive, 512kB Cache, DMA
> media-bay 0 is ide2
> mediabay 0 IDE ready
> 
> 	Regards,
> 	Gabriel