Re: [PATCH v2 03/10] e1000e: Support RXFCS feature flag.
From: Michał Mirosław <hidden>
Date: 2012-02-10 23:09:27
W dniu 10 lutego 2012 23:57 użytkownik Ben Greear [off-list ref] napisał:
On 02/10/2012 02:46 PM, Michał Mirosław wrote:quoted
2012/2/8[off-list ref]:quoted
From: Ben Greear<redacted> This enables enabling/disabling reception of the Ethernet FCS. This can be useful when sniffing packets. For e1000e, enabling RXFCS can change the default behaviour for how the NIC handles CRC. Disabling RXFCS will take the NIC back to defaults, which can be configured as part of the module options.[...] This is not how I would expect the features to behave. Default value should be set on probe() time, and when you disable RXFCS it should just get disabled.The NIC itself may still receive the FCS, but it will be removed before the pkt is sent up the stack once you disable the 'rx-fcs' flag. My goal was to make sure that if you enabled and then disabled the new rx-fcs flag, then you would be back at the original behaviour. I think that if the "rx-fcs off" logic is to change the default behaviour, then the Intel folks probably need to make those changes: It seems that there are some tricky work-arounds regarding fcs and segmented packets for at least some versions of the e1000e chipsets.
That makes sense. The flag FLAG2_DFLT_CRC_STRIPPING should be called FLAG2_FORCE_CRC_STRIPPING_OFF or something if that's the case. "Default" doesn't tell if that's a strong preference or just because. Best Regards, Michał Mirosław