[PATCH net-next 2/2] sfc: only fall back to a lower interrupt mode if it is supported

[Edward Cree]

From: Andrew Rybchenko <andrew.rybche...@oktetlabs.ru>

If we fail to probe interrupts with our minimum mode, return that error.

Signed-off-by: Edward Cree <ec...@solarflare.com>
---
 drivers/net/ethernet/sfc/efx.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 88a9f97..8c4c273 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -1420,9 +1420,12 @@ static int efx_probe_interrupts(struct efx_nic *efx)
                                           xentries, 1, n_channels);
                if (rc < 0) {
                        /* Fall back to single channel MSI */
-                       efx->interrupt_mode = EFX_INT_MODE_MSI;
                        netif_err(efx, drv, efx->net_dev,
                                  "could not enable MSI-X\n");
+                       if (efx->type->min_interrupt_mode >= EFX_INT_MODE_MSI)
+                               efx->interrupt_mode = EFX_INT_MODE_MSI;
+                       else
+                               return rc;
                } else if (rc < n_channels) {
                        netif_err(efx, drv, efx->net_dev,
                                  "WARNING: Insufficient MSI-X vectors"
@@ -1465,7 +1468,10 @@ static int efx_probe_interrupts(struct efx_nic *efx)
                } else {
                        netif_err(efx, drv, efx->net_dev,
                                  "could not enable MSI\n");
-                       efx->interrupt_mode = EFX_INT_MODE_LEGACY;
+                       if (efx->type->min_interrupt_mode >= 
EFX_INT_MODE_LEGACY)
+                               efx->interrupt_mode = EFX_INT_MODE_LEGACY;
+                       else
+                               return rc;
                }
        }