Messages in this thread | | | Date | Thu, 17 Apr 2008 12:38:19 -0700 | From | "Yinghai Lu" <> | Subject | Re: [PATCH] x86_64: restore mask_bits in msi shutdown |
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On Thu, Apr 17, 2008 at 3:15 AM, Eric W. Biederman <ebiederm@xmission.com> wrote: > Hmm. Trying this again with what should be yh's proper address. > > > > Yinghai Lu <yhlu.kernel.send@gmail.com> writes: > > > > > I can not kexec RHEL 5.1 from 2.6.25-rc3 later > > > > caused by: > > commit 89d694b9dbe769ca1004e01db0ca43964806a611 > > Author: Thomas Gleixner <tglx@linutronix.de> > > Date: Mon Feb 18 18:25:17 2008 +0100 > > > > genirq: do not leave interupts enabled on free_irq > > > > The default_disable() function was changed in commit: > > > > 76d2160147f43f982dfe881404cfde9fd0a9da21 > > genirq: do not mask interrupts by default > > > > It removed the mask function in favour of the default delayed > > interrupt disabling. Unfortunately this also broke the shutdown in > > free_irq() when the last handler is removed from the interrupt for > > those architectures which rely on the default implementations. Now we > > can end up with a enabled interrupt line after the last handler was > > removed, which can result in spurious interrupts. > > > > Fix this by adding a default_shutdown function, which is only > > installed, when the irqchip implementation does provide neither a > > shutdown nor a disable function. > > > > [@stable: affected versions: .21 - .24 ] > > > > > > > > for MSI, default_shutdown will call mask_bit for msi device. so all mask bits > > will > > left disabled after free_irq. > > then if kexec next kernel that only can use msi_enable bit. > > all device's MSI can not be used. > > > > So try to restore MSI mask bits that is saved before using msi in first kernel. > > > > Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> > > > Ouch! In the case of MSI-X this is horrible. Reenabling an interrupt > line when we are not using it. That is likely to cause even stranger > things than kexec to fail.
yes It doesn't restore that for MSI-X
> > What happens when someone next comes to use that msi interrupt is > a reasonable question.
it uses MSI, but doesn't touch mask_bits
> > The PCI standard describes the state the bits in the msi capability > are supposed to be in after reset, and if a driver is going to > assume some state that is the only reasonable state for a driver to > expect the hardware to be in. So we don't need to perform a > save/restore cycle. > > Could you look at having pci_disable_msi reset the mask bit > to it's default state after we have called msi_set_enable(dev, 0)? > Once the msi capability is disabled the mask bit has no affect.
but the next kernel (RHEL 5.1) only can enable msi, and it doesn't touch mask_bits (that is leaved as 0xff by first 2.6.25-rc2 later) so device (nvidia mcp55 nic) doesn't work. --- if i manually used setpci to set 0x60 to 0xfe or 0x00. it will work. also if i booted kernel (RHEL 5.1), that 0x60 is always 0x00, even nic works with MSI.
YH
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