Re: [Intel-wired-lan] [PATCH v4] e1000e: Increase polling timeout on MDIC ready bit

From: Vitaly Lifshits
Date: Wed Sep 30 2020 - 02:54:46 EST


On 9/29/2020 18:08, Kai-Heng Feng wrote:

Hello Kai-Heng,


On Sep 29, 2020, at 21:46, Neftin, Sasha <sasha.neftin@xxxxxxxxx> wrote:

Hello Kai-Heng,
On 9/29/2020 16:31, Kai-Heng Feng wrote:
Hi Sasha,
On Sep 29, 2020, at 21:08, Neftin, Sasha <sasha.neftin@xxxxxxxxx> wrote:

On 9/28/2020 11:36, Kai-Heng Feng wrote:
We are seeing the following error after S3 resume:
[ 704.746874] e1000e 0000:00:1f.6 eno1: Setting page 0x6020
[ 704.844232] e1000e 0000:00:1f.6 eno1: MDI Write did not complete
[ 704.902817] e1000e 0000:00:1f.6 eno1: Setting page 0x6020
[ 704.903075] e1000e 0000:00:1f.6 eno1: reading PHY page 769 (or 0x6020 shifted) reg 0x17
[ 704.903281] e1000e 0000:00:1f.6 eno1: Setting page 0x6020
[ 704.903486] e1000e 0000:00:1f.6 eno1: writing PHY page 769 (or 0x6020 shifted) reg 0x17
[ 704.943155] e1000e 0000:00:1f.6 eno1: MDI Error
...
[ 705.108161] e1000e 0000:00:1f.6 eno1: Hardware Error
As Andrew Lunn pointed out, MDIO has nothing to do with phy, and indeed
increase polling iteration can resolve the issue.
This patch only papers over the symptom, as we don't really know the
root cause of the issue. The most possible culprit is Intel ME, which
may do its own things that conflict with software.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
---
v4:
- States that this patch just papers over the symptom.
v3:
- Moving delay to end of loop doesn't save anytime, move it back.
- Point out this is quitely likely caused by Intel ME.
v2:
- Increase polling iteration instead of powering down the phy.
drivers/net/ethernet/intel/e1000e/phy.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/e1000e/phy.c b/drivers/net/ethernet/intel/e1000e/phy.c
index e11c877595fb..e6d4acd90937 100644
--- a/drivers/net/ethernet/intel/e1000e/phy.c
+++ b/drivers/net/ethernet/intel/e1000e/phy.c
@@ -203,7 +203,7 @@ s32 e1000e_write_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 data)
* Increasing the time out as testing showed failures with
* the lower time out
*/
- for (i = 0; i < (E1000_GEN_POLL_TIMEOUT * 3); i++) {
+ for (i = 0; i < (E1000_GEN_POLL_TIMEOUT * 10); i++) {
As we discussed (many threads) - AMT/ME systems not supported on Linux as properly. I do not think increasing polling iteration will solve the problem. Rather mask it.
I am aware of the status quo of no proper support on Intel ME.
I prefer you check option to disable ME vi BIOS on your system.
We can't ask user to change the BIOS to accommodate Linux. So before a proper solution comes out, masking the problem is good enough for me.
Until then, I'll carry it as a downstream distro patch.
What will you do with system that even after increasing polling time will run into HW error?

Hope we finally have proper ME support under Linux?

Kai-Heng

Kai-Heng
udelay(50);
mdic = er32(MDIC);
if (mdic & E1000_MDIC_READY)
Thanks,
Sasha
Thanks,
Sasha


On which device ID/platform do you see the issue? What is the Firmware version on your platform? What is the ME firmware version that you have?

I am asking these questions, since I know there is supposed to be a fix in the firmware to many issues that are related to ME and device interoperability.

Thanks,

Vitaly