On 01/22/2016 09:53 AM, Bjorn Helgaas wrote:
On Thu, Jan 21, 2016 at 11:58:26PM +0100, Rafael J. Wysocki wrote:
On Thu, Jan 21, 2016 at 3:41 PM, Cao jin <caoj.fnst@xxxxxxxxxxxxxx> wrote:
Hi,
IMHO, I think maybe modification on i801_smbus driver is easier.
Because when i801_smbus request_irq using pci_dev->irq, this
pci_dev->irq seems still holds the value read from register(
pci_setup_device->pci_read_irq), if the value is 255, it is invalid in
register,
Right.
Which is why the PCI core should not leak it into the driver's ->probe callback.
Is there a reserved IRQ value we could use to mean "invalid"?
In many (most) cases, zero indicates no irq.
I guess we have NR_IRQS as a ceiling, so the range of valid IRQs would be
[0 .. NR_IRQS - 1]. It looks like irq_desc() and a few drivers already
rely on NR_IRQS being the bound:
lpc32xx_kscan_probe
lpc32xx_nand_probe
pcmcia_setup_isa_irq
lpc32xx_rtc_probe
apbuart_verify_port
ar933x_uart_verify_port
lqasc_verify_port
So I guess we could use ~0 as "invalid IRQ", and maybe the PCI core could
set dev->irq to ~0 in these cases, and drivers like i801_smbus could check
for that. Maybe a wrapper like irq_valid() would be useful.
Bjorn
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