| Message ID | 20180914154811.12090-1-nicolas.ferre@microchip.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | net: macb: disable scatter-gather for macb on sama5d3 | expand |
From: Nicolas Ferre <nicolas.ferre@microchip.com> Date: Fri, 14 Sep 2018 17:48:10 +0200 > Create a new configuration for the sama5d3-macb new compatibility string. > This configuration disables scatter-gather because we experienced lock down > of the macb interface of this particular SoC under very high load. > > Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com> Applied, but are you really sure it isn't just some bug in the driver or somesuch?
On 17/09/2018 at 16:58, David Miller wrote: > From: Nicolas Ferre <nicolas.ferre@microchip.com> > Date: Fri, 14 Sep 2018 17:48:10 +0200 > >> Create a new configuration for the sama5d3-macb new compatibility string. >> This configuration disables scatter-gather because we experienced lock down >> of the macb interface of this particular SoC under very high load. >> >> Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com> > > Applied, but are you really sure it isn't just some bug in the driver > or somesuch? Actually, the same IP on other SoCs behaves correctly with same driver. We tried hard to find the root cause of the problem without success and we didn't have confirmation of an issue on Cadence's side either. The symptom is that we have a receive overrun on this interface under heavy load but I think that it is more a result of the issue than the real problem: I cannot escape from this overrun condition: the IP itself is completely blocked. Even if the problem is very difficult to reproduce (simple *perf tools not sufficient), we play safe by simply disabling this feature on this SoC only. Best regards,
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index 16e4ef7d7185..f1a86b422617 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -3837,6 +3837,13 @@ static const struct macb_config at91sam9260_config = { .init = macb_init, }; +static const struct macb_config sama5d3macb_config = { + .caps = MACB_CAPS_SG_DISABLED + | MACB_CAPS_USRIO_HAS_CLKEN | MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII, + .clk_init = macb_clk_init, + .init = macb_init, +}; + static const struct macb_config pc302gem_config = { .caps = MACB_CAPS_SG_DISABLED | MACB_CAPS_GIGABIT_MODE_AVAILABLE, .dma_burst_length = 16, @@ -3904,6 +3911,7 @@ static const struct of_device_id macb_dt_ids[] = { { .compatible = "cdns,gem", .data = &pc302gem_config }, { .compatible = "atmel,sama5d2-gem", .data = &sama5d2_config }, { .compatible = "atmel,sama5d3-gem", .data = &sama5d3_config }, + { .compatible = "atmel,sama5d3-macb", .data = &sama5d3macb_config }, { .compatible = "atmel,sama5d4-gem", .data = &sama5d4_config }, { .compatible = "cdns,at91rm9200-emac", .data = &emac_config }, { .compatible = "cdns,emac", .data = &emac_config },
Create a new configuration for the sama5d3-macb new compatibility string. This configuration disables scatter-gather because we experienced lock down of the macb interface of this particular SoC under very high load. Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com> --- drivers/net/ethernet/cadence/macb_main.c | 8 ++++++++ 1 file changed, 8 insertions(+)