On Fri, Jul 25, 2014 at 05:30:48PM -0600, Stephen Warren wrote: > From: Stephen Warren <[email protected]> > > Currently, the BOOTP code sends out its initial request as soon as the > Ethernet driver indicates "link up". If this packet is lost or not > replied to for some reason, the code waits for a 1s timeout before > retrying. For some reason, such early packets are often lost on my > system, so this causes an annoying delay. > > To optimize this, modify the BOOTP code to have very short timeouts for > the first packet transmitted, but gradually increase the timeout each > time a timeout occurs. This way, if the first packet is lost, the second > packet is transmitted quite quickly and hence the overall delay is low. > However, if there's still no response, we don't keep spewing out packets > at an insane speed. > > It's arguably more correct to try and find out why the first packet is > lost. However, it seems to disappear inside my Ethenet chip; the TX chip > indicates no error during TX (not that it has much in the way of > reporting...), yet wireshark on the RX side doesn't see any packet. > FWIW, I'm using an ASIX USB Ethernet adapter. Perhaps "link up" is > reported too early or based on the wrong condition in HW, and we should > add some fixed extra delay into the driver. However, this would slow down > every link up event even if it ends up not being needed in some cases. > Having BOOTP retry quickly applies the fix/WAR to every possible > Ethernet device, and is quite simple to implement, so seems a better > solution. > > Signed-off-by: Stephen Warren <[email protected]> > --- > net/bootp.c | 38 +++++++++++++++++++++++++++++++------- > net/bootp.h | 3 +-- > net/net.c | 4 ++-- > 3 files changed, 34 insertions(+), 11 deletions(-)
Sorry for jumping in a little late, but I only encountered this after rebasing on latest origin/master today. With this patch applied, it takes about 8 seconds until U-Boot manages to get a DHCP address (it needs to broadcast 14 times) whereas with the patch reverted I get a reply almost instantly (with only a single broadcast). I'm testing this on a Jetson TK1 (with local patches for PCIe and ethernet support). Thierry
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