On 8/6/2019 18:53, mario.limoncie...@dell.com wrote:
-----Original Message-----
From: Paul Menzel <pmen...@molgen.mpg.de>
Sent: Tuesday, August 6, 2019 10:36 AM
To: Jeff Kirsher
Cc: intel-wired-...@lists.osuosl.org; Linux Kernel Mailing List; Limonciello,
Mario
Subject: MDI errors during resume from ACPI S3 (suspend to ram)
Dear Linux folks,
Trying to decrease the resume time of Linux 5.3-rc3 on the Dell OptiPlex
5040 with the device below
$ lspci -nn -s 00:1f.6
00:1f.6 Ethernet controller [0200]: Intel Corporation Ethernet Connection
(2)
I219-V [8086:15b8] (rev 31)
pm-graph’s script `sleepgraph.py` shows, that the driver *e1000e* takes
around 400 ms, which is quite a lot. The call graph trace shows that
`e1000e_read_phy_reg_mdic()` is responsible for a lot of those. From
`drivers/net/ethernet/intel/e1000e/phy.c` [1]:
for (i = 0; i < (E1000_GEN_POLL_TIMEOUT * 3); i++) {
udelay(50);
mdic = er32(MDIC);
if (mdic & E1000_MDIC_READY)
break;
}
if (!(mdic & E1000_MDIC_READY)) {
e_dbg("MDI Read did not complete\n");
return -E1000_ERR_PHY;
}
if (mdic & E1000_MDIC_ERROR) {
e_dbg("MDI Error\n");
return -E1000_ERR_PHY;
}
Unfortunately, errors are not logged if dynamic debug is disabled,
so rebuilding the Linux kernel with `CONFIG_DYNAMIC_DEBUG`, and
echo "file drivers/net/ethernet/* +p" | sudo tee
/sys/kernel/debug/dynamic_debug/control
I got the messages below.
[ 4159.204192] e1000e 0000:00:1f.6 net00: MDI Error
[ 4160.267950] e1000e 0000:00:1f.6 net00: MDI Write did not complete
[ 4160.359855] e1000e 0000:00:1f.6 net00: MDI Error
Can you please shed a little more light into these errors? Please
find the full log attached.
Kind regards,
Paul
[1]:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/n
et/ethernet/intel/e1000e/phy.c#n206
Strictly as a reference point you may consider trying the out-of-tree driver to
see if these
behaviors persist.
https://sourceforge.net/projects/e1000/
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We are using external PHY. Required ~200 ms to complete MDIC transaction
(depended on the project). You need to take to consider this time before
access to the PHY. I do not recommend decrease timer in a
'e1000e_read_phy_reg_mdic()' method. We could hit on wrong MDI access.
