RE: [PATCH net 1/2] r8152: fix the sw rx checksum is unavailable
From: Hayes Wang
Date: Wed Nov 23 2016 - 10:12:48 EST
Mark Lord [mlord@xxxxxxxxx]
> What does this code do:
> >static void r8153_set_rx_early_size(struct r8152 *tp)
> > u32 mtu = tp->netdev->mtu;
> > u32 ocp_data = (agg_buf_sz - mtu - VLAN_ETH_HLEN - VLAN_HLEN) / 4;
> > ocp_write_word(tp, MCU_TYPE_USB, USB_RX_EARLY_SIZE, ocp_data);
This only works for RTL8153. However, what you use is RTL8152.
It is like delay completion. It is used to reduce the loading of CPU
by letting a transfer contain more data to reduce the number of
> How is ocp_data used by the hardware?
> Shouldn't the calculation also include sizeof(rx_desc) in there somewhere?
The algorithm is from our hw engineers, and it should be
(agg_buf_sz - packet size) / 8
You could refer to commit a59e6d815226 ("r8152: correct the rx early size").