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r8169: confusion between hardware and IP header alignment 

The rx copybreak part is straightforward.

The align field in struct rtl_cfg_info is related to the alignment
requirements of the DMA operation. Its value is set at 2 to limit the
scale of possible regression but my old v1.21 8169 datasheet claims a
8 bytes requirements (which never appeared in the driver, of course)
and the 8101/8168 go with a plain 8 bytes alignment.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Cc: Edward Hsu <edward_hsu@realtek.com.tw>
This commit is contained in:
Francois Romieu 2007-02-20 22:20:51 +01:00 committed by Jeff Garzik
parent 0e4851502f
commit 864022344c
1 changed files with 5 additions and 7 deletions
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12
drivers/net/r8169.c
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@ -1490,7 +1490,7 @@ static const struct rtl_cfg_info {
[RTL_CFG_0] = {
.hw_start = rtl_hw_start_8169,
.region = 1,
.align = NET_IP_ALIGN,
.align = 2,
.intr_event = SYSErr | LinkChg | RxOverflow |
RxFIFOOver | TxErr | TxOK | RxOK | RxErr,
.napi_event = RxFIFOOver | TxErr | TxOK | RxOK | RxOverflow
@ -2649,8 +2649,7 @@ static inline void rtl8169_rx_csum(struct sk_buff *skb, struct RxDesc *desc)
}
static inline bool rtl8169_try_rx_copy(struct sk_buff **sk_buff, int pkt_size,
struct pci_dev *pdev, dma_addr_t addr,
unsigned int align)
struct pci_dev *pdev, dma_addr_t addr)
{
struct sk_buff *skb;
bool done = false;
@ -2658,12 +2657,12 @@ static inline bool rtl8169_try_rx_copy(struct sk_buff **sk_buff, int pkt_size,
if (pkt_size >= rx_copybreak)
goto out;
skb = dev_alloc_skb(pkt_size + align);
skb = dev_alloc_skb(pkt_size + NET_IP_ALIGN);
if (!skb)
goto out;
pci_dma_sync_single_for_cpu(pdev, addr, pkt_size, PCI_DMA_FROMDEVICE);
skb_reserve(skb, (align - 1) & (unsigned long)skb->data);
skb_reserve(skb, NET_IP_ALIGN);
skb_copy_from_linear_data(*sk_buff, skb->data, pkt_size);
*sk_buff = skb;
done = true;
@ -2732,8 +2731,7 @@ rtl8169_rx_interrupt(struct net_device *dev, struct rtl8169_private *tp,
rtl8169_rx_csum(skb, desc);
if (rtl8169_try_rx_copy(&skb, pkt_size, pdev, addr,
tp->align)) {
if (rtl8169_try_rx_copy(&skb, pkt_size, pdev, addr)) {
pci_dma_sync_single_for_device(pdev, addr,
pkt_size, PCI_DMA_FROMDEVICE);
rtl8169_mark_to_asic(desc, tp->rx_buf_sz);