[src/trunk]: src/sys/dev/pci/ixgbe Fix a bug that INTx is disabled if the INT...

[msaitoh <msaitoh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/76b625fae915
branches:  trunk
changeset: 948294:76b625fae915
user:      msaitoh <msaitoh%NetBSD.org@localhost>
date:      Thu Dec 24 18:32:53 2020 +0000

description:
Fix a bug that INTx is disabled if the INTx line is shared with other device.
ixgbe.c rev. 1.264 was not correct.

     Restore EIMS before return. To read ECIR, clearing EIMC is required for
    an errata, so
        0) save the original EIMS value
        1) clear EIMS
        2) read EICR
        3) restore with the saved value.

diffstat:

 sys/dev/pci/ixgbe/ixgbe.c |  10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diffs (33 lines):

diff -r 6f53093a07f9 -r 76b625fae915 sys/dev/pci/ixgbe/ixgbe.c
--- a/sys/dev/pci/ixgbe/ixgbe.c Thu Dec 24 15:51:33 2020 +0000
+++ b/sys/dev/pci/ixgbe/ixgbe.c Thu Dec 24 18:32:53 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: ixgbe.c,v 1.268 2020/12/24 15:51:33 msaitoh Exp $ */
+/* $NetBSD: ixgbe.c,v 1.269 2020/12/24 18:32:53 msaitoh Exp $ */
 
 /******************************************************************************
 
@@ -5161,9 +5161,14 @@
        bool            more = false;
        bool            reenable_intr = true;
        u32             eicr, eicr_mask;
+       u32             eims_orig;
        u32             task_requests = 0;
 
-       /* Silicon errata #26 on 82598. Disable all interrupts */
+       eims_orig = IXGBE_READ_REG(hw, IXGBE_EIMS);
+       /*
+        * Silicon errata #26 on 82598. Disable all interrupts before reading
+        * EICR.
+        */
        IXGBE_WRITE_REG(hw, IXGBE_EIMC, IXGBE_IRQ_CLEAR_MASK);
 
        /* Read and clear EICR */
@@ -5173,6 +5178,7 @@
        ++que->irqs.ev_count;
        if (eicr == 0) {
                adapter->stats.pf.intzero.ev_count++;
+               IXGBE_WRITE_REG(hw, IXGBE_EIMS, eims_orig);
                return 0;
        }