> -----Original Message----- > From: mika.westerberg@xxxxxxxxxxxxxxx > [mailto:mika.westerberg@xxxxxxxxxxxxxxx] > Sent: 13 November 2018 12:59 > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx> > Cc: linux-pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Wangzhou (B) > <wangzhou1@xxxxxxxxxxxxx>; Linuxarm <linuxarm@xxxxxxxxxx>; Lukas > Wunner <lukas@xxxxxxxxx> > Subject: Re: Qemu Guest kernel 4.20-rc1 PCIe hotplug issue > > On Tue, Nov 13, 2018 at 12:36:20PM +0000, Shameerali Kolothum Thodi wrote: > > > @@ -156,9 +156,9 @@ static void pcie_do_write_cmd(struct controller > > > *ctrl, > > > u16 cmd, > > > slot_ctrl |= (cmd & mask); > > > ctrl->cmd_busy = 1; > > > smp_mb(); > > > + ctrl->slot_ctrl = slot_ctrl; > > > > Actually I tried this one, but it doesn't help in this case as the > > initial > > pcie_capability_read_word() returns the slot_ctrl without > > PCI_EXP_SLTCTL_HPIE bit set. It looks to me > > pcie_enable_notification() function enables this, > > > > if (!pciehp_poll_mode) > > cmd |= PCI_EXP_SLTCTL_HPIE | PCI_EXP_SLTCTL_CCIE; > > > > I don't know this is as per the spec or not as the initial cap read > > doesn't seems to have the PCI_EXP_SLTCTL_HPIE bit set. > > If I read the code right cmd value should end up in ctrl->slot_ctrl properly from > pcie_enable_notification(). Right. As I mentioned in my previous mail, I missed the fact that you are updating the ctrl->slot_ctrl with cmd value while in my test I did my update with the value returned by pcie_capability_read_word(). > However, I think we are missing check for PCI_EXP_SLTCTL_CCIE in > pciehp_isr(). Ok. > Here's an updated patch, can you try and see if it makes any difference? I just tried this and it works. Thanks. See few comments below. > diff --git a/drivers/pci/hotplug/pciehp_hpc.c > b/drivers/pci/hotplug/pciehp_hpc.c > index 7dd443aea5a5..da2cbe892444 100644 > --- a/drivers/pci/hotplug/pciehp_hpc.c > +++ b/drivers/pci/hotplug/pciehp_hpc.c > @@ -156,9 +156,9 @@ static void pcie_do_write_cmd(struct controller *ctrl, > u16 cmd, > slot_ctrl |= (cmd & mask); > ctrl->cmd_busy = 1; > smp_mb(); > + ctrl->slot_ctrl = slot_ctrl; Does it make more sense if we can move this before smp_mb()?. Also I am not sure updating the ctrl->slot_ctrl before actually the hardware is programmed with that value will result in any other race conditions? TBH, I am not that familiar with this code and I leave that to you :) Thanks, Shameer > pcie_capability_write_word(pdev, PCI_EXP_SLTCTL, slot_ctrl); > ctrl->cmd_started = jiffies; > - ctrl->slot_ctrl = slot_ctrl; > > /* > * Controllers with the Intel CF118 and similar errata advertise @@ - > 522,7 +522,7 @@ static irqreturn_t pciehp_isr(int irq, void *dev_id) > * in the Slot Control register (PCIe r4.0, sec 6.7.3.4). > */ > if (pdev->current_state == PCI_D3cold || > - (!(ctrl->slot_ctrl & PCI_EXP_SLTCTL_HPIE) && !pciehp_poll_mode)) > + (!(ctrl->slot_ctrl & (PCI_EXP_SLTCTL_HPIE | PCI_EXP_SLTCTL_CCIE)) > +&& !pciehp_poll_mode)) > return IRQ_NONE; > > /*
