Yinghai Lu wrote:
On 10/15/07, Jeff Garzik <[EMAIL PROTECTED]> wrote:
Manfred Spraul wrote:
Jeff Garzik wrote:
I think the scenario you outline is an illustration of the approach's
fragility: disable_irq() is a heavy hammer that originated with INTx,
and it relies on a chip-specific disable method (kernel/irq/manage.c)
that practically guarantees behavior will vary across MSI/INTx/etc.
I checked the code: IRQ_DISABLE is implemented in software, i.e.
handle_level_irq() only calls handle_IRQ_event() [and then the nic irq
handler] if IRQ_DISABLE is not set.
OTHO: The last trace looks as if nv_do_nic_poll() is interrupted by an irq.
Perhaps something corrupts dev->irq? The irq is requested with
request_irq(np->pci_dev->irq, handler, IRQF_SHARED, dev->name, dev)
and disabled with
disable_irq_lockdep(dev->irq);
Someone around with a MSI capable board? The forcedeth driver does
dev->irq = pci_dev->irq
in nv_probe(), especially before pci_enable_msi().
Does pci_enable_msi() change pci_dev->irq? Then we would disable the
wrong interrupt....
Remember, fundamentally MSI-X is a one-to-many relationship, when you
consider a single PCI device might have multiple vectors.
msi-x is using other entry
if (np->msi_flags & NV_MSI_X_ENABLED)
enable_irq_lockdep(np->msi_x_entry[NV_MSI_X_VECTOR_ALL].vector);
Correct, but the overall point was that MSI-X conceptually conflicts
with the existing "lockless" disable_irq() schedule, which was written
when there was a one-one relationship between irq, PCI device, and work
to be done.
Jeff
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
