On 3/12/19 3:20 PM, Lukas Wunner wrote:
> On Tue, Mar 12, 2019 at 03:05:48PM +0300, Sergey Miroshnichenko wrote:
>> During the safe removal procedure, a Data Link Layer State Changed event
>> may occur after pciehp_power_off_slot(), and it is handled when the slot is
>> already set to OFF_STATE. This results in re-enabling the device and makes
>> it impossible to actually safely remove it.
>>
>> Clear out the Presence Detect Changed and Data Link Layer State Changed
>> events when the disabled slot has settled down.
>>
>> It is still possible to re-enable the device if it remains in the slot
>> after pressing the Attention Button by pressing it again.
>>
>> Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko@xxxxxxxxx>
>
> Reviewed-by: Lukas Wunner <lukas@xxxxxxxxx>
>
Thank you!
> Did this work correctly before v4.19 or is it a regression caused by
> d331710ea78f ("PCI: pciehp: Become resilient to missed events")?
> Either way, it seems reasonable to backport it to stable and
> v4.19 is the earliest that it should apply cleanly to, so:
>
> Cc: stable@xxxxxxxxxxxxxxx # v4.19+
>
Yes, that was a regression caused by this commit. I've verified it
applies cleanly to v4.19.
Best regards,
Serge
> Thanks a lot for catching this, I wasn't able to test the code paths
> which are only exercised if a power controller is present (because
> Thunderbolt doesn't have one).
>
> Lukas
>
>> ---
>> drivers/pci/hotplug/pciehp_ctrl.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
>> index 3f3df4c29f6e..905282a8ddaa 100644
>> --- a/drivers/pci/hotplug/pciehp_ctrl.c
>> +++ b/drivers/pci/hotplug/pciehp_ctrl.c
>> @@ -115,6 +115,10 @@ static void remove_board(struct controller *ctrl, bool safe_removal)
>> * removed from the slot/adapter.
>> */
>> msleep(1000);
>> +
>> + /* Ignore link or presence changes caused by power off */
>> + atomic_and(~(PCI_EXP_SLTSTA_DLLSC | PCI_EXP_SLTSTA_PDC),
>> + &ctrl->pending_events);
>> }
>>
>> /* turn off Green LED */
>> --
>> 2.20.1
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