Thread (13 messages) 13 messages, 5 authors, 2019-12-10

Re: [PATCH net] net: mvpp2: fix condition for setting up link interrupt

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From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Date: 2019-12-08 16:43:01
Also in: lkml

On Fri, Jan 25, 2019 at 09:37:20AM +0100, Antoine Tenart wrote:
quoted hunk ↗ jump to hunk
Hi,

On Thu, Jan 24, 2019 at 04:07:41PM +0000, Russell King - ARM Linux admin wrote:
quoted
On Thu, Jan 24, 2019 at 04:51:37PM +0100, Andrew Lunn wrote:
quoted
On Thu, Jan 24, 2019 at 02:18:03PM +0100, Thomas Bogendoerfer wrote:
quoted
Fixes: 4bb043262878 ("net: mvpp2: phylink support")
Signed-off-by: Thomas Bogendoerfer <redacted>
---
 drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index 16066c2d5b3a..0fbfe1945a69 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -3405,7 +3405,7 @@ static int mvpp2_open(struct net_device *dev)
 		valid = true;
 	}
 
-	if (priv->hw_version == MVPP22 && port->link_irq && !port->phylink) {
+	if (priv->hw_version == MVPP22 && port->link_irq && port->phylink) {
 		err = request_irq(port->link_irq, mvpp2_link_status_isr, 0,
 				  dev->name, port);
 		if (err) {
This still looks fishy to me.  mvpp2_link_status_isr() has handling in
it that is safe to be called for non-phylink cases, so presumably the
right fix is to drop the "&& !port->phylink" completely?
That's right, mvpp2_link_status_isr() is safe to be called with or
without phylink being used. This IRQ is reporting the link status, and
is used when using in-band status or when phylink isn't used.

We do have a similar fix locally, which looks like:
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index 2bcbf9caaf0d..6bab1824a1e4 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -3406,7 +3406,8 @@ static int mvpp2_open(struct net_device *dev)
                valid = true;
        }

-       if (priv->hw_version == MVPP22 && port->link_irq && !port->phylink) {
+       if (priv->hw_version == MVPP22 && port->link_irq &&
+           (!port->phylink || !port->has_phy)) {
                err = request_irq(port->link_irq, mvpp2_link_status_isr, 0,
                                  dev->name, port);
                if (err) {
We haven't submitted it yet, as we saw several issues when a port has no
PHY and is using the XLG MAC (so, not on the mcbin). We currently are
working on them.

I don't like to ask this, as you submitted the fix first, but I do think
we should hold back a bit while we figure out proper solutions. If you
need in-band status to be working properly, we could share out current
local branch so you can test and validate it do solve your issue.
Hi Antoine,

Today, I received an email from Willy Tarreau about this issue which
persists to this day with mainline kernels.

Willy reminded me that I've been carrying a fix for this, but because
of your concerns as stated above, I haven't bothered submitting it
through fear of causing regressions (which you seem to know about):

   http://git.armlinux.org.uk/cgit/linux-arm.git/commit/?h=mvpp2&id=67ef3bff255b26cc0d6def8ca99c4e8ae9937727

Just like Thomas' case, the current code is broken for phylink when
in-band negotiation is being used - such as with the 1G/2.5G SFP
slot on the Macchiatobin.

It seems that resolving the issue has stalled.  Can I merge my patch,
or could you state exactly what the problems are with it so that
someone else can look into the issues please?

Thanks.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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