[U-Boot] [PATCH] net: Improve the speed of netconsole

[Stefano Babic <sbabic@denx.de>]

On 24/07/2012 22:11, Joe Hershberger wrote:
> Previously u-boot would initialize the network interface for every
> network operation and then shut it down again.  This makes sense for
> most operations where the network in not known to be needed soon after
> the operation is complete.  In the case of netconsole, it will use the
> network for every interaction with the shell or every printf.  This
> means that the network is being reinitialized very often.  On many
> devices, this intialization is very slow.

Hi Joe,

agree with you - and in some cases, such as ethernet on USB, netconsole
is not yet useful.

Which is the status of the ethernet controller before starting the
kernel ? Up now we guarantee that the hardware is turned off before
kernel takes over. This patch changes this behavior, and I know from the
past (really with USB, we have a usb_stop before calling the kernel)
that this can be dangerous.

Maybe you can add a eth_halt() call into do_bootm().

Second general question is if the behavior of
CONFIG_NETCONSOLE_PERSIST_ETH should be always turned on when Netconsole
is activated. I mean, your patch maintain a high compatibility with the
past, but I suppose that everyone using netconsole likes the new
behavior that you are introducing and everyone will turn
CONFIG_NETCONSOLE_PERSIST_ETH on. Then we can simply use
CONFIG_NETCONSOLE as switch.

Best regards,
Stefano

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