Messages in this thread | | | Date | Wed, 13 May 2015 20:07:05 +0200 | From | Robert Richter <> | Subject | Re: [PATCH v2] AHCI: Add generic MSI-X interrupt support to SATA PCI driver |
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On 13.05.15 13:46:40, Tejun Heo wrote: > Hello, Robert. > > On Wed, May 13, 2015 at 07:28:28PM +0200, Robert Richter wrote: > > > > This looks not very useful to do. Since irq is used only a single > > > > time, there is no reason to store it in the host's data structure. It > > > > > > Doesn't really matter tho. > > > > Since ahci_host_activate() is EXPORT_SYMBOL_GPL I really have concerns > > changing the i/f. But I will send you a patch for this. > > It doesn't matter. Please go ahead and change it.
Ok, np.
> > > Let's start with why we're doing this in the first place. > > > > Right, the sata controller is connected to a pci ecam controller, both > > are on an SoC together with the processor. There are no external pci > > ports for the connection of external devices. Since all pci devices on > > the chip support msi-x, the controller is only capable to handle this > > and not INTx nor MSI. So for enabling of the sata hc we need msix > > support. > > I see. If you can get hold of an ahci controller which actually can > do multi-irq msix, it'd be the best. If not, let's make it super > clear that this is a special case and use it as the last resort (which > also clers up the warning issue).
This sounds good.
The device actually supports multi-irq msix, a single mode interrupt + additional interrupts for error or hotplug handling. But I don't have hardware for a per-port msix host controller.
So I will move msix after msi then and mark it as a special case if msi is not supported. I don't want to move it after intx since this is the fallback if nothing else works, there is no explicit check for intx, I even don't know if that is possible at all.
Thanks,
-Robert
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