diff options
| author | Ben Hutchings <bhutchings@solarflare.com> | 2011-09-01 12:09:29 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-09-15 17:31:28 -0400 |
| commit | 86c432ca5d6da90a26ac8d3e680f2268b502d9c5 (patch) | |
| tree | 6db2e039f5cecfbc1643f46e2da5c18ae9aaabe5 /drivers/net/sfc/efx.c | |
| parent | 883cb075833e7e4356207569e0daefa2c2a3f700 (diff) | |
Revert "sfc: Use write-combining to reduce TX latency" and follow-ups
This reverts commits 65f0b417dee94f779ce9b77102b7d73c93723b39,
d88d6b05fee3cc78e5b0273eb58c31201dcc6b76,
fcfa060468a4edcf776f0c1211d826d5de1668c1,
747df2258b1b9a2e25929ef496262c339c380009 and
867955f5682f7157fdafe8670804b9f8ea077bc7.
Depending on the processor model, write-combining may result in
reordering that the NIC will not tolerate. This typically results
in a DMA error event and reset by the driver, logged as:
sfc 0000:0e:00.0: eth2: TX DMA Q reports TX_EV_PKT_ERR.
sfc 0000:0e:00.0: eth2: resetting (ALL)
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/sfc/efx.c')
| -rw-r--r-- | drivers/net/sfc/efx.c | 18 |
1 files changed, 2 insertions, 16 deletions
diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c index faca764aa21b..b59abc706d93 100644 --- a/drivers/net/sfc/efx.c +++ b/drivers/net/sfc/efx.c @@ -1050,7 +1050,6 @@ static int efx_init_io(struct efx_nic *efx) { struct pci_dev *pci_dev = efx->pci_dev; dma_addr_t dma_mask = efx->type->max_dma_mask; - bool use_wc; int rc; netif_dbg(efx, probe, efx->net_dev, "initialising I/O\n"); @@ -1101,21 +1100,8 @@ static int efx_init_io(struct efx_nic *efx) rc = -EIO; goto fail3; } - - /* bug22643: If SR-IOV is enabled then tx push over a write combined - * mapping is unsafe. We need to disable write combining in this case. - * MSI is unsupported when SR-IOV is enabled, and the firmware will - * have removed the MSI capability. So write combining is safe if - * there is an MSI capability. - */ - use_wc = (!EFX_WORKAROUND_22643(efx) || - pci_find_capability(pci_dev, PCI_CAP_ID_MSI)); - if (use_wc) - efx->membase = ioremap_wc(efx->membase_phys, - efx->type->mem_map_size); - else - efx->membase = ioremap_nocache(efx->membase_phys, - efx->type->mem_map_size); + efx->membase = ioremap_nocache(efx->membase_phys, + efx->type->mem_map_size); if (!efx->membase) { netif_err(efx, probe, efx->net_dev, "could not map memory BAR at %llx+%x\n", |