lkml.org 
[lkml]   [2021]   [Aug]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 3/3] e1000e: Serialize TGP e1000e PM ops
From
Date
On 7/27/2021 09:53, Kai-Heng Feng wrote:
> Hi Sasha,
>
> On Mon, Jul 12, 2021 at 9:35 PM Kai-Heng Feng
> <kai.heng.feng@canonical.com> wrote:
>>
>> On TGL systems, PCI_COMMAND may randomly flip to 0 on system resume.
>> This is devastating to drivers that use pci_set_master(), like NVMe and
>> xHCI, to enable DMA in their resume routine, as pci_set_master() can
>> inadvertently disable PCI_COMMAND_IO and PCI_COMMAND_MEMORY, making
>> resources inaccessible.
>>
>> The issue is reproducible on all kernel releases, but the situation is
>> exacerbated by commit 6cecf02e77ab ("Revert "e1000e: disable s0ix entry
>> and exit flows for ME systems"").
>>
>> Seems like ME can do many things to other PCI devices until it's finally out of
>> ULP polling. So ensure e1000e PM ops are serialized by enforcing suspend/resume
>> order to workaround the issue.
>>
>> Of course this will make system suspend and resume a bit slower, but we
>> probably need to settle on this workaround until ME is fully supported.
>>
>> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=212039
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>
> Series "e1000e: Add handshake with the CSME to support s0ix" doesn't
> fix the issue, so this patch is still needed.
Hello Kai-Heng,
This problem is still under investigation by the ME team. Let's wait for
their response.
Series "e1000e: Add handshake with the CSME to support s0ix" - support
only s0ix flow on AMT/CSME none provisioned systems and not related to
this problem.
>
> Kai-Heng
>
>> ---
>> drivers/net/ethernet/intel/e1000e/netdev.c | 14 +++++++++++++-
>> 1 file changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
>> index e63445a8ce12..0244d3dd90a3 100644
>> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
>> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
>> @@ -7319,7 +7319,8 @@ static const struct net_device_ops e1000e_netdev_ops = {
>>
>> static void e1000e_create_device_links(struct pci_dev *pdev)
>> {
>> - struct pci_dev *tgp_mei_me;
>> + struct pci_bus *bus = pdev->bus;
>> + struct pci_dev *tgp_mei_me, *p;
>>
>> /* Find TGP mei_me devices and make e1000e power depend on mei_me */
>> tgp_mei_me = pci_get_device(PCI_VENDOR_ID_INTEL, 0xa0e0, NULL);
>> @@ -7335,6 +7336,17 @@ static void e1000e_create_device_links(struct pci_dev *pdev)
>> pci_info(pdev, "System and runtime PM depends on %s\n",
>> pci_name(tgp_mei_me));
>>
>> + /* Find other devices in the SoC and make them depend on e1000e */
>> + list_for_each_entry(p, &bus->devices, bus_list) {
>> + if (&p->dev == &pdev->dev || &p->dev == &tgp_mei_me->dev)
>> + continue;
>> +
>> + if (device_link_add(&p->dev, &pdev->dev,
>> + DL_FLAG_AUTOREMOVE_SUPPLIER))
>> + pci_info(p, "System PM depends on %s\n",
>> + pci_name(pdev));
>> + }
>> +
>> pci_dev_put(tgp_mei_me);
>> }
>>
>> --
>> 2.31.1
>>
sasha

\
 
 \ /
  Last update: 2021-08-01 06:16    [W:0.057 / U:1.360 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site