Re: [PATCH 05/12] genirq: Shutdown irq chips in suspend/resume during hibernation
CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe. On 5/19/20 7:26 PM, Anchal Agarwal wrote: > Many legacy device drivers do not implement power management (PM) > functions which means that interrupts requested by these drivers stay > in active state when the kernel is hibernated. > > This does not matter on bare metal and on most hypervisors because the > interrupt is restored on resume without any noticable side effects as > it stays connected to the same physical or virtual interrupt line. > > The XEN interrupt mechanism is different as it maintains a mapping > between the Linux interrupt number and a XEN event channel. If the > interrupt stays active on hibernation this mapping is preserved but > there is unfortunately no guarantee that on resume the same event > channels are reassigned to these devices. This can result in event > channel conflicts which prevent the affected devices from being > restored correctly. > > One way to solve this would be to add the necessary power management > functions to all affected legacy device drivers, but that's a > questionable effort which does not provide any benefits on non-XEN > environments. > > The least intrusive and most efficient solution is to provide a > mechanism which allows the core interrupt code to tear down these > interrupts on hibernation and bring them back up again on resume. This > allows the XEN event channel mechanism to assign an arbitrary event > channel on resume without affecting the functionality of these > devices. > > Fortunately all these device interrupts are handled by a dedicated XEN > interrupt chip so the chip can be marked that all interrupts connected > to it are handled this way. This is pretty much in line with the other > interrupt chip specific quirks, e.g. IRQCHIP_MASK_ON_SUSPEND. > > Add a new quirk flag IRQCHIP_SHUTDOWN_ON_SUSPEND and add support for > it the core interrupt suspend/resume paths. > > Signed-off-by: Anchal Agarwal > Signed-off--by: Thomas Gleixner Since Thomas wrote this patch I think it should also have "From: " him. That sounds about right. I will update it next round and add Tested-by. -boris - Anchal
Re: [PATCH 05/12] genirq: Shutdown irq chips in suspend/resume during hibernation
On 5/19/20 7:26 PM, Anchal Agarwal wrote: > Many legacy device drivers do not implement power management (PM) > functions which means that interrupts requested by these drivers stay > in active state when the kernel is hibernated. > > This does not matter on bare metal and on most hypervisors because the > interrupt is restored on resume without any noticable side effects as > it stays connected to the same physical or virtual interrupt line. > > The XEN interrupt mechanism is different as it maintains a mapping > between the Linux interrupt number and a XEN event channel. If the > interrupt stays active on hibernation this mapping is preserved but > there is unfortunately no guarantee that on resume the same event > channels are reassigned to these devices. This can result in event > channel conflicts which prevent the affected devices from being > restored correctly. > > One way to solve this would be to add the necessary power management > functions to all affected legacy device drivers, but that's a > questionable effort which does not provide any benefits on non-XEN > environments. > > The least intrusive and most efficient solution is to provide a > mechanism which allows the core interrupt code to tear down these > interrupts on hibernation and bring them back up again on resume. This > allows the XEN event channel mechanism to assign an arbitrary event > channel on resume without affecting the functionality of these > devices. > > Fortunately all these device interrupts are handled by a dedicated XEN > interrupt chip so the chip can be marked that all interrupts connected > to it are handled this way. This is pretty much in line with the other > interrupt chip specific quirks, e.g. IRQCHIP_MASK_ON_SUSPEND. > > Add a new quirk flag IRQCHIP_SHUTDOWN_ON_SUSPEND and add support for > it the core interrupt suspend/resume paths. > > Signed-off-by: Anchal Agarwal > Signed-off--by: Thomas Gleixner Since Thomas wrote this patch I think it should also have "From: " him. -boris
Re: [PATCH 05/12] genirq: Shutdown irq chips in suspend/resume during hibernation
Thanks. Looks like send an old one without fix. Did resend the patch again. On Tue, 2020-05-19 at 23:26 +, Anchal Agarwal wrote: > Signed-off--by: Thomas Gleixner The Signed-off-by line needs to be fixed (hint: you have --) Balbir Singh
Re: [PATCH 05/12] genirq: Shutdown irq chips in suspend/resume during hibernation
On Tue, 2020-05-19 at 23:26 +, Anchal Agarwal wrote: > Signed-off--by: Thomas Gleixner The Signed-off-by line needs to be fixed (hint: you have --) Balbir Singh
