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SubjectRe: [PATCH v2] e1000e: Add a delay to let ME unconfigure s0ix when DPG_EXIT_DONE is already flagged
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On 10/27/2021 01:50, Kai-Heng Feng wrote:
> On Tue, Oct 26, 2021 at 4:48 PM Sasha Neftin <sasha.neftin@intel.com> wrote:
>>
>> On 10/26/2021 09:51, Kai-Heng Feng wrote:
>>> On some ADL platforms, DPG_EXIT_DONE is always flagged so e1000e resume
>>> polling logic doesn't wait until ME really unconfigures s0ix.
>>>
>>> So check DPG_EXIT_DONE before issuing EXIT_DPG, and if it's already
>>> flagged, wait for 1 second to let ME unconfigure s0ix.
>>>
>>> Fixes: 3e55d231716e ("e1000e: Add handshake with the CSME to support S0ix")
>>> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214821
>>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>>> ---
>>> v2:
>>> Add missing "Fixes:" tag
>>>
>>> drivers/net/ethernet/intel/e1000e/netdev.c | 7 +++++++
>>> 1 file changed, 7 insertions(+)
>>>
>>> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
>>> index 44e2dc8328a22..cd81ba00a6bc9 100644
>>> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
>>> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
>>> @@ -6493,14 +6493,21 @@ static void e1000e_s0ix_exit_flow(struct e1000_adapter *adapter)
>>> u32 mac_data;
>>> u16 phy_data;
>>> u32 i = 0;
>>> + bool dpg_exit_done;
>>>
>>> if (er32(FWSM) & E1000_ICH_FWSM_FW_VALID) {
>>> + dpg_exit_done = er32(EXFWSM) & E1000_EXFWSM_DPG_EXIT_DONE;
>>> /* Request ME unconfigure the device from S0ix */
>>> mac_data = er32(H2ME);
>>> mac_data &= ~E1000_H2ME_START_DPG;
>>> mac_data |= E1000_H2ME_EXIT_DPG;
>>> ew32(H2ME, mac_data);
>>>
>>> + if (dpg_exit_done) {
>>> + e_warn("DPG_EXIT_DONE is already flagged. This is a firmware bug\n");
>>> + msleep(1000);
>>> + }
>> Thanks for working on the enablement.
>> The delay approach is fragile. We need to work with CSME folks to
>> understand why _DPG_EXIT_DONE indication is wrong on some ADL platforms.
>> Could you provide CSME/BIOS version? dmidecode -t 0 and cat
>> /sys/class/mei/mei0/fw_ver
>
> $ sudo dmidecode -t 0
> # dmidecode 3.2
> Getting SMBIOS data from sysfs.
> SMBIOS 3.4 present.
> # SMBIOS implementations newer than version 3.2.0 are not
> # fully supported by this version of dmidecode.
>
> Handle 0x0001, DMI type 0, 26 bytes
> BIOS Information
> Vendor: Dell Inc.
> Version: 0.12.68
> Release Date: 10/01/2021
> ROM Size: 48 MB
> Characteristics:
> PCI is supported
> PNP is supported
> BIOS is upgradeable
> BIOS shadowing is allowed
> Boot from CD is supported
> Selectable boot is supported
> EDD is supported
> Print screen service is supported (int 5h)
> 8042 keyboard services are supported (int 9h)
> Serial services are supported (int 14h)
> Printer services are supported (int 17h)
> ACPI is supported
> USB legacy is supported
> BIOS boot specification is supported
> Function key-initiated network boot is supported
> Targeted content distribution is supported
> UEFI is supported
> BIOS Revision: 0.12
>
> $ cat /sys/class/mei/mei0/fw_ver
> 0:16.0.15.1518
> 0:16.0.15.1518
> 0:16.0.15.1518
>
Thank you Kai-Heng. The _DPG_EXIT_DONE bit indication comes from the
EXFWSM register controlled by the CSME. We have only read access. I
realized that this indication was set to 1 even before our request to
unconfigure the s0ix settings from the CSME. I am wondering. Does after
a ~ 1s delay (or less, or more) _DPG_EXIT_DONE indication eventually
change by CSME to 0? (is it consistently)
>>> /* Poll up to 2.5 seconds for ME to unconfigure DPG.
>>> * If this takes more than 1 second, show a warning indicating a
>>> * firmware bug
>>>

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