Re: MSI changes in .28

[Yinghai Lu]

On Fri, Dec 5, 2008 at 12:53 AM, Frans Pop <elendil@xxxxxxxxx> wrote:
> On Tuesday 02 December 2008, Linus Torvalds wrote:
>> So, it looks like you have MSI enabled in -rc6, and not in -rc3.
>
> I've just compared dmesg for my *desktop* and there I see the following
> between 2.6.28-rc6 and current 2.6.28-rc7:
>
>  pcieport-driver 0000:00:1c.0: setting latency timer to 64
>  pcieport-driver 0000:00:1c.0: found MSI capability
> -pcieport-driver 0000:00:1c.0: irq 47 for MSI/MSI-X
> +pcieport-driver 0000:00:1c.0: irq 511 for MSI/MSI-X
>  pci_express 0000:00:1c.0:pcie00: allocate port service
>  pci_express 0000:00:1c.0:pcie02: allocate port service
>  pcieport-driver 0000:00:1c.2: setting latency timer to 64
>  pcieport-driver 0000:00:1c.2: found MSI capability
> -pcieport-driver 0000:00:1c.2: irq 46 for MSI/MSI-X
> +pcieport-driver 0000:00:1c.2: irq 510 for MSI/MSI-X
>  pci_express 0000:00:1c.2:pcie00: allocate port service
>  pci_express 0000:00:1c.2:pcie02: allocate port service
>  pcieport-driver 0000:00:1c.3: setting latency timer to 64
>  pcieport-driver 0000:00:1c.3: found MSI capability
> -pcieport-driver 0000:00:1c.3: irq 45 for MSI/MSI-X
> +pcieport-driver 0000:00:1c.3: irq 509 for MSI/MSI-X
>  pci_express 0000:00:1c.3:pcie00: allocate port service
>  pci_express 0000:00:1c.3:pcie02: allocate port service
>  pcieport-driver 0000:00:1c.4: setting latency timer to 64
>  pcieport-driver 0000:00:1c.4: found MSI capability
> -pcieport-driver 0000:00:1c.4: irq 44 for MSI/MSI-X
> +pcieport-driver 0000:00:1c.4: irq 508 for MSI/MSI-X
>  pci_express 0000:00:1c.4:pcie00: allocate port service
>  pci_express 0000:00:1c.4:pcie02: allocate port service
>  pcieport-driver 0000:00:1c.5: setting latency timer to 64
>  pcieport-driver 0000:00:1c.5: found MSI capability
> -pcieport-driver 0000:00:1c.5: irq 43 for MSI/MSI-X
> +pcieport-driver 0000:00:1c.5: irq 507 for MSI/MSI-X
> [...]
>  ahci 0000:00:1f.2: PCI INT B -> GSI 19 (level, low) -> IRQ 19
> -ahci 0000:00:1f.2: irq 42 for MSI/MSI-X
> +ahci 0000:00:1f.2: irq 506 for MSI/MSI-X
>  ahci 0000:00:1f.2: AHCI 0001.0100 32 slots 4 ports 3 Gbps 0xf impl SATA mode
> [...]
>  e1000e 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
>  e1000e 0000:01:00.0: setting latency timer to 64
> -e1000e 0000:01:00.0: irq 41 for MSI/MSI-X
> +e1000e 0000:01:00.0: irq 505 for MSI/MSI-X
>
> I.e. very similar to the change between rc-3 and rc-7 you commented on
> for my notebook.
>
> Is this really MSI being (not) enabled, or just it using much higher
> IRQ numbers?

because NR_IRQS is increased. and MSI irq is back counting from NR_IRQS - 1.

we have patch in sparse_irq, will start dyn irq for MSI from
nr_irqs_gsi ( the max irq ioapic will use) .. ( according to Thomas)

before that reach mainline, the effects for you is wasting some space
from some big irq_desc[].
but only 450... that is not bad.

YH
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/