Re: [PATCH V2] PCI/portdrv: do not disable device on reboot/shutdown

Sinan Kaya
2018-05-24T11:43:05Z

On 5/23/2018 6:57 PM, Sinan Kaya wrote:
>> The crash seems to indicate that the hpsa device attempted a DMA after
>> we cleared the Root Port's PCI_COMMAND_MASTER, which means
>> hpsa_shutdown() didn't stop DMA from the device (it looks like *most*
>> shutdown methods don't disable device DMA, so it's in good company).
> All drivers are expected to shutdown DMA and interrupts in their shutdown()
> routines. They can skip removing threads, data structures etc. but DMA and
> interrupt disabling are required. This is the difference between shutdown()
> and remove() callbacks.

I found this note yesterday to see why we are not disabling the devices in the
PCI core itself.

pci_device_remove()

/*
* We would love to complain here if pci_dev->is_enabled is set, that
* the driver should have called pci_disable_device(), but the
* unfortunate fact is there are too many odd BIOS and bridge setups
* that don't like drivers doing that all of the time.
* Oh well, we can dream of sane hardware when we sleep, no matter how
* horrible the crap we have to deal with is when we are awake...
*/

Ryan, can you discard the previous patch and test this one instead? remove() path
in hpsa driver seems to call pci_disable_device() via

hpsa_remove_one()
hpsa_free_pci_init()

but nothing on the shutdown path.

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 4ed3d26..3823f04 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -8651,6 +8651,7 @@ static void hpsa_shutdown(struct pci_dev *pdev)
h->access.set_intr_mask(h, HPSA_INTR_OFF);
hpsa_free_irqs(h); /* init_one 4 */
hpsa_disable_interrupt_mode(h); /* pci_init 2 */
+ pci_disable_device(h->pdev);
}

--
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.