no link changed interrupt

no link changed interrupt

[Walser, Martin]

Hi,

I'm using kernel 2.4.4.
The problem is, that I get no link changed interrupt when connecting or
disconnectiong the ethernet. I'm using the DP83846 from National. There is no
hardware interrupt, but it's possible to generate an interrupt flag in a special
register
Is it possible to get this software interrupt in the fec.c ?
Is there another way to get a link change without a hardware interrupt?

best regard
Martin


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Re: no link changed interrupt

[Dan Malek]

Walser, Martin wrote:

> Is there another way to get a link change without a hardware interrupt?

The only way to guarantee a link chnage interrupt is to use a PHY and
board design that supports a hardware interrupt.  Some boards/PHYs do
this, others do not, and it is a board specific design.  While you could
poll the PHY status at regular intervals, it would depend upon the PHY
status registers to properly publish/latch this information.  There isn't
sufficient information in the generic PHY registers to detect link change,
so again this is software that will have to be implemented unique to your
PHY (it's proprietary registers) and board design.

The only reason the FEC (or any 8xx/82xx Ethernet controller) needs to
see a link change is to properly configure full/half duplex.  It will
adapt to the different link speeds and other link attributes.


	-- Dan


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RE: no link changed interrupt

[Jean-Denis Boyer]

Martin,

> Is there another way to get a link change without a hardware
> interrupt?

Take a look at the following threads of discussion.

Titled: MPC8xx, FEC and DP83847 !?
http://lists.linuxppc.org/linuxppc-embedded/200203/threads4.html#00171

Titled: Patch for linux/arch/ppc/8xx_io/fec.c
http://lists.linuxppc.org/linuxppc-embedded/200203/threads5.html#00200

Regards,

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 Jean-Denis Boyer, B.Eng., System Architect
 Mediatrix Telecom Inc.
 4229 Garlock Street
 Sherbrooke (Québec)
 J1L 2C8  CANADA
 (819)829-8749 x241
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