Re: alpha runtime warnings due to commit 0e4c2eeb758 ("alpha/PCI: Replace pci_fixup_irqs() call with host ...")

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Tue, Sep 19, 2017 at 11:02:33AM -0700, Guenter Roeck wrote:
> On Tue, Sep 19, 2017 at 10:12:32AM +0100, Lorenzo Pieralisi wrote:
> > On Mon, Sep 18, 2017 at 07:00:55PM -0700, Guenter Roeck wrote:
> > > Hi,
> > > 
> > > I see the following runtime warnings in mainline when running alpha images in qemu.
> > > 
> > > 
> > > Floppy drive(s): fd0 is 2.88M
> > > ide0: disabled, no IRQ
> > > ide0: failed to initialize IDE interface
> > > ide0: disabling port
> > > cmd64x 0000:00:02.0: IDE controller (0x1095:0x0646 rev 0x07)
> > > CMD64x_IDE 0000:00:02.0: BAR 0: can't reserve [io  0x8050-0x8057]
> > > cmd64x 0000:00:02.0: can't reserve resources
> > > CMD64x_IDE: probe of 0000:00:02.0 failed with error -16
> > > ide_generic: please use "probe_mask=0x3f" module parameter for probing all legacy ISA IDE ports
> > > ------------[ cut here ]------------
> > > WARNING: CPU: 0 PID: 1 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x94/0xd0
> > > sysfs: cannot create duplicate filename '/class/ide_port/ide0'
> > > ...
> > > 
> > > Trace:
> > > [<fffffc00003308a0>] __warn+0x160/0x190
> > > [<fffffc000048c9f4>] sysfs_warn_dup+0x94/0xd0
> > > [<fffffc0000330928>] warn_slowpath_fmt+0x58/0x70
> > > [<fffffc000048c9f4>] sysfs_warn_dup+0x94/0xd0
> > > [<fffffc0000486d40>] kernfs_path_from_node+0x30/0x60
> > > [<fffffc00004874ac>] kernfs_put+0x16c/0x2c0
> > > [<fffffc00004874ac>] kernfs_put+0x16c/0x2c0
> > > [<fffffc000048d010>] sysfs_do_create_link_sd.isra.2+0x100/0x120
> > > [<fffffc00005b9d64>] device_add+0x2a4/0x7c0
> > > [<fffffc00005ba5cc>] device_create_groups_vargs+0x14c/0x170
> > > [<fffffc00005ba518>] device_create_groups_vargs+0x98/0x170
> > > [<fffffc00005ba690>] device_create+0x50/0x70
> > > [<fffffc00005df36c>] ide_host_register+0x48c/0xa00
> > > [<fffffc00005df330>] ide_host_register+0x450/0xa00
> > > [<fffffc00005ba2a0>] device_register+0x20/0x50
> > > [<fffffc00005df330>] ide_host_register+0x450/0xa00
> > > [<fffffc00005df944>] ide_host_add+0x64/0xe0
> > > [<fffffc000079b41c>] kobject_uevent_env+0x16c/0x710
> > > [<fffffc0000310288>] do_one_initcall+0x68/0x260
> > > [<fffffc00007b13bc>] kernel_init+0x1c/0x1a0
> > > [<fffffc00007b13a0>] kernel_init+0x0/0x1a0
> > > [<fffffc0000311868>] ret_from_kernel_thread+0x18/0x20
> > > [<fffffc00007b13a0>] kernel_init+0x0/0x1a0
> > > 
> > > ---[ end trace 24a70433c3e4d374 ]---
> > > ide0: disabling port
> > > 
> > > [ multiple times ]
> > > 
> > > A complete log is available at http://kerneltests.org/builders/qemu-alpha-master.
> > > 
> > > Prior to the offending commit, the kernel log looks as follows.
> > > 
> > > ...
> > > Uniform Multi-Platform E-IDE driver
> > > cmd64x 0000:00:02.0: IDE controller (0x1095:0x0646 rev 0x07)
> > > cmd64x 0000:00:02.0: IDE port disabled
> > > cmd64x 0000:00:02.0: 100% native mode on irq 28
> > > PCI: Setting latency timer of device 0000:00:02.0 to 64
> > >     ide0: BM-DMA at 0x8040-0x8047
> > > Floppy drive(s): fd0 is 2.88M
> > > ide0 at 0x8050-0x8057,0x8062 on irq 28 (serialized)
> > > ide_generic: please use "probe_mask=0x3f" module parameter for probing all legacy ISA IDE ports
> > > ide1 at 0x1f0-0x1f7,0x3f6 on irq 14
> > > ide2 at 0x170-0x177,0x376 on irq 15
> > > ide-gd driver 1.18
> > > ide-cd driver 5.00
> > > ...
> > > 
> > > Reverting the commit is not possible due to context changes.
> > > 
> > > Bisect log is attached.
> > 
> > Ok thanks. Can you please check if the diff below fixes the issue ?
> > 
> It does. Feel free to add
> 
> Tested-by: Guenter Roeck <linux@roeck-us.net>
> 
> to the actual patch.
> 
> > I think the problem is that now we allocate the IRQ at device_probe
> > instead of device_add time, if the patch below fixes the issue the
> > question is whether we want to move pci_assign_irq() to pci_device_add()
> > for ALL PCI devices or just fix this for IDE subsytem.
> > 
> 
> That I can not answer ...

It is not a clean-cut answer. Moving pci_assign_irq() from

pci_device_probe()

to

pci_device_add()

would fix this issue too and just map/swizzle() irqs for ALL PCI devices
earlier (even ones that are not even probed); it should have no side
effects (famous last words) and would be a cleaner fix.

Fix below is fine but I am not a big fan of it, I would like to
get Bjorn's opinion before I send a fix out.

Thanks,
Lorenzo

> Guenter
> 
> > Lorenzo
> > 
> > -- >8 --
> > diff --git a/drivers/ide/setup-pci.c b/drivers/ide/setup-pci.c
> > index 112d2fe..94ca9cc 100644
> > --- a/drivers/ide/setup-pci.c
> > +++ b/drivers/ide/setup-pci.c
> > @@ -502,6 +502,8 @@ static int do_ide_setup_pci_device(struct pci_dev *dev,
> >  {
> >  	int pciirq, ret;
> >  
> > +	pci_assign_irq(dev);
> > +
> >  	/*
> >  	 * Can we trust the reported IRQ?
> >  	 */