Florian
On 1/31/20 1:29 PM, Florian Fainelli wrote:
On 1/31/20 11:14 AM, Dan Murphy wrote:
Florian
On 1/31/20 12:42 PM, Florian Fainelli wrote:
On 1/31/20 10:29 AM, Dan Murphy wrote:
Florian
On 1/31/20 11:49 AM, Florian Fainelli wrote:
On 1/31/20 7:11 AM, Dan Murphy wrote:
Set the speed optimization bit on the DP83867 PHY.
This feature can also be strapped on the 64 pin PHY devices
but the 48 pin devices do not have the strap pin available to enable
this feature in the hardware. PHY team suggests to have this bit set.
OK, but why and how does that optimization work exactly?
I described this in the cover letter. And it is explained in the data
sheet Section 8.4.6.6
Sorry I complete missed that and just focused on the patch, you should
consider not providing a cover letter for a single patch, and especially
not when the cover letter contains more information than the patch
commit message itself.
Sorry I usually give a cover letter to all my network related patches.
Unless I misinterpreted David on his reply to me about cover letters.
https://www.spinics.net/lists/netdev/msg617575.html
This was a 2 patches series, for which a cover letter is mandatory:
but for single patches, there really is no need, and having to replicate
the same information in two places is just error prone.
And I seemed to have missed David on the --cc list so I will add him for
v2.
I was also asked not to provide the same information in the cover letter
and the commit message.
The cover letter is meant to provide some background about choices you
have made, or how to merge the patches, or their dependencies, and
describe the changes in a big picture. The patches themselves are
supposed to be comprehensive.
As always thank you for the guidance. I will update the commit with
better information and remove the cover letter.
Either way I am ok with not providing a cover letter and updating the
commit message with more information.
Departing from
the BMSR reads means you possibly are going to introduce bugs and/or
incomplete information. For instance, you set phydev->pause and
phydev->asym_pause to 0 now, is there no way to extract what the link
partner has advertised?
I was using the marvel.c as my template as it appears to have a separate
status register as well.
Instead of setting those bits in the call back I can call the
genphy_read_status then override the duplex and speed based on the
physts register like below. This way link status and pause values can
be updated and then we can update the speed and duplex settings.
ret = genphy_read_status(phydev);
if (ret)
return ret;
if (status < 0)
return status;
if (status & DP83867_PHYSTS_DUPLEX)
phydev->duplex = DUPLEX_FULL;
else
phydev->duplex = DUPLEX_HALF;
if (status & DP83867_PHYSTS_1000)
phydev->speed = SPEED_1000;
else if (status & DP83867_PHYSTS_100)
phydev->speed = SPEED_100;
else
phydev->speed = SPEED_10;
OK, but what if they disagree, are they consistently latched with
respect to one another?
Well in parsing through the code for genphy read status when auto
negotiation is set the phydev structure appears to be setup per what has
been configured. I did not see any reading of speed or duplex when auto
neg is set it is just taking the LPA register. But I am probably not
right here. So we and our customers found that the phy was always
reporting a 1Gbps connection when the 4 wire cable connected when using
genphy_read_status. This PHYSTS register provides a single location
within the register set for quick access to commonly accessed
information.
That is the kind of information that you want to put in the commit
message, and that sounds like a Fix more than a feature to me. If the
BMSR is not reflecting the correct speed, clearly something is not quite
good. You may also consider reflecting whether downshift was in action
and that led to reducing the speed, something like
m88e1011_link_change_notify() does.
But what is it fixing? When the driver was originally submitted it was
meant to be a Giga bit PHY. No requirement for any connection less then
1Gbps. Now we have a customer who wants to use this feature and they
want it upstreamed. (YAY for them pushing upstream).
Do I reference my original commit? Because I am actually flipping the
bits to turn it on as well only way this was a fix is if the user had
the feature strapped to on. But to date we have not had any requests
for this support.
So then it would be ok to do a genphy_read_status and then override the
speed and duplex mode from the PHYSTS register?
I don't think that the link change notification is needed. The speed
should not change once the cable is plugged in and the speed is negotiated.
Dan
