[PATCH] Read back MSI message in rtas_setup_msi_irqs() so restore works

[PATCH] Read back MSI message in rtas_setup_msi_irqs() so restore works

[Michael Ellerman]

There are plans afoot to use pci_restore_msi_state() to restore MSI
state after a device reset. In order for this to work for the RTAS MSI
backend, we need to read back the MSI message from config space after
it has been setup by firmware.

This should be sufficient for restoring the MSI state after a device
reset, however we will need to revisit this for suspend to disk if that
is ever implemented on pseries.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
---

Linas, can you test this on your setup with your EEH stuff? I haven't got
any MSI supporting hardware/firmware combination.


 arch/powerpc/platforms/pseries/msi.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/msi.c b/arch/powerpc/platforms/pseries/msi.c
index 2793a1b..f15222b 100644
--- a/arch/powerpc/platforms/pseries/msi.c
+++ b/arch/powerpc/platforms/pseries/msi.c
@@ -171,6 +171,7 @@ static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
 	struct pci_dn *pdn;
 	int hwirq, virq, i, rc;
 	struct msi_desc *entry;
+	struct msi_msg msg;
 
 	pdn = get_pdn(pdev);
 	if (!pdn)
@@ -213,6 +214,11 @@ static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
 
 		dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq);
 		set_irq_msi(virq, entry);
+
+		/* Read config space back so we can restore after reset */
+		read_msi_msg(virq, &msg);
+		entry->msg = msg;
+
 		unmask_msi_irq(virq);
 	}
 
-- 
1.5.1.3.g7a33b

Re: [PATCH] Read back MSI message in rtas_setup_msi_irqs() so restore works

[Linas Vepstas]

On Tue, Oct 23, 2007 at 02:23:44PM +1000, Michael Ellerman wrote:
> There are plans afoot to use pci_restore_msi_state() to restore MSI
> state after a device reset. In order for this to work for the RTAS MSI
> backend, we need to read back the MSI message from config space after
> it has been setup by firmware.
> 
> This should be sufficient for restoring the MSI state after a device
> reset, however we will need to revisit this for suspend to disk if that
> is ever implemented on pseries.
> 
> Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
> ---
> 
> Linas, can you test this on your setup with your EEH stuff? I haven't got
> any MSI supporting hardware/firmware combination.

Acked-by: Linas Vepstas <linas@austin.ibm.com>

I *finally* was able to get onto some hardware long enough to run this.
And that took a lot of work. Sigh. Yes, this is exactly what I'd wanted.

--linas