Message ID | 20181203070517.22668-1-zhengxiang9@huawei.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | pcie: set link state inactive/active after hot unplug/plug | expand |
On 12/3/18 9:05 AM, Zheng Xiang wrote: > When VM boots from the latest version of linux kernel, after > hot-unpluging virtio-blk disks which are hotplugged into > pcie-root-port, the VM's dmesg log shows: > > [ 151.046242] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0001 from Slot Status > [ 151.046365] pciehp 0000:00:05.0:pcie004: Slot(0-3): Attention button pressed > [ 151.046369] pciehp 0000:00:05.0:pcie004: Slot(0-3): Powering off due to button press > [ 151.046420] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > [ 151.046425] pciehp 0000:00:05.0:pcie004: pciehp_green_led_blink: SLOTCTRL a8 write cmd 200 > [ 151.046464] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > [ 151.046468] pciehp 0000:00:05.0:pcie004: pciehp_set_attention_status: SLOTCTRL a8 write cmd c0 > [ 156.163421] pciehp 0000:00:05.0:pcie004: pciehp_get_power_status: SLOTCTRL a8 value read 2f1 > [ 156.163427] pciehp 0000:00:05.0:pcie004: pciehp_unconfigure_device: domain:bus:dev = 0000:06:00 > [ 156.198736] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > [ 156.198772] pciehp 0000:00:05.0:pcie004: pciehp_power_off_slot: SLOTCTRL a8 write cmd 400 > [ 157.224124] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0018 from Slot Status > [ 157.224194] pciehp 0000:00:05.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 write cmd 300 > [ 157.224220] pciehp 0000:00:05.0:pcie004: pciehp_check_link_active: lnk_status = 2011 > [ 157.224223] pciehp 0000:00:05.0:pcie004: Slot(0-3): Link Up > [ 157.224233] pciehp 0000:00:05.0:pcie004: pciehp_get_power_status: SLOTCTRL a8 value read 7f1 > [ 157.224281] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > [ 157.224285] pciehp 0000:00:05.0:pcie004: pciehp_power_on_slot: SLOTCTRL a8 write cmd 0 > [ 157.224300] pciehp 0000:00:05.0:pcie004: __pciehp_link_set: lnk_ctrl = 0 > [ 157.224336] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > [ 157.224339] pciehp 0000:00:05.0:pcie004: pciehp_green_led_blink: SLOTCTRL a8 write cmd 200 > [ 159.739294] pci 0000:06:00.0 id reading try 50 times with interval 20 ms to get ffffffff > [ 159.739315] pciehp 0000:00:05.0:pcie004: pciehp_check_link_status: lnk_status = 2011 > [ 159.739318] pciehp 0000:00:05.0:pcie004: Failed to check link status > [ 159.739371] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > [ 159.739394] pciehp 0000:00:05.0:pcie004: pciehp_power_off_slot: SLOTCTRL a8 write cmd 400 > [ 160.771426] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > [ 160.771452] pciehp 0000:00:05.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 write cmd 300 > [ 160.771495] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > [ 160.771499] pciehp 0000:00:05.0:pcie004: pciehp_set_attention_status: SLOTCTRL a8 write cmd 40 > [ 160.771535] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > [ 160.771539] pciehp 0000:00:05.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 write cmd 300 > > After analyzing the log information, it seems that qemu doesn't > change the Link Status from active to inactive after hot-unplug. > This results in the abnormal log after the linux kernel commit > d331710ea78fea merged. > > Furthermore, If I hotplug the same virtio-blk disk after hot-unplug, > the virtio-blk would turn on and then back off. > > So this patch set the Link Status inactive after hot-unplug and > active after hot-plug. > > Signed-off-by: Zheng Xiang <zhengxiang9@huawei.com> > Signed-off-by: Zheng Xiang <xiang.zheng@linaro.org> > Cc: Wang Haibin <wanghaibin.wang@huawei.com> > --- > hw/pci/pcie.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c > index 6c91bd4..66b73b8 100644 > --- a/hw/pci/pcie.c > +++ b/hw/pci/pcie.c > @@ -345,6 +345,10 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev, > if (!dev->hotplugged) { > pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, > PCI_EXP_SLTSTA_PDS); > + if (pci_dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) { > + pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA, > + PCI_EXP_LNKSTA_DLLLA); > + } > return; > } > > @@ -355,6 +359,10 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev, > if (pci_get_function_0(pci_dev)) { > pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, > PCI_EXP_SLTSTA_PDS); > + if (pci_dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) { > + pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA, > + PCI_EXP_LNKSTA_DLLLA); > + } > pcie_cap_slot_event(PCI_DEVICE(hotplug_dev), > PCI_EXP_HP_EV_PDC | PCI_EXP_HP_EV_ABP); > } > @@ -531,6 +539,10 @@ void pcie_cap_slot_write_config(PCIDevice *dev, > > pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA, > PCI_EXP_SLTSTA_PDS); > + if (dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) { > + pci_word_test_and_clear_mask(exp_cap + PCI_EXP_LNKSTA, > + PCI_EXP_LNKSTA_DLLLA); > + } > pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, > PCI_EXP_SLTSTA_PDC); > } Looks good to me, Reviewed-by: Marcel Apfelbaum<marcel.apfelbaum@gmail.com> Thanks, Marcel
On Wed, Dec 05, 2018 at 08:23:35AM +0200, Marcel Apfelbaum wrote: > > > On 12/3/18 9:05 AM, Zheng Xiang wrote: > > When VM boots from the latest version of linux kernel, after > > hot-unpluging virtio-blk disks which are hotplugged into > > pcie-root-port, the VM's dmesg log shows: > > > > [ 151.046242] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0001 from Slot Status > > [ 151.046365] pciehp 0000:00:05.0:pcie004: Slot(0-3): Attention button pressed > > [ 151.046369] pciehp 0000:00:05.0:pcie004: Slot(0-3): Powering off due to button press > > [ 151.046420] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > > [ 151.046425] pciehp 0000:00:05.0:pcie004: pciehp_green_led_blink: SLOTCTRL a8 write cmd 200 > > [ 151.046464] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > > [ 151.046468] pciehp 0000:00:05.0:pcie004: pciehp_set_attention_status: SLOTCTRL a8 write cmd c0 > > [ 156.163421] pciehp 0000:00:05.0:pcie004: pciehp_get_power_status: SLOTCTRL a8 value read 2f1 > > [ 156.163427] pciehp 0000:00:05.0:pcie004: pciehp_unconfigure_device: domain:bus:dev = 0000:06:00 > > [ 156.198736] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > > [ 156.198772] pciehp 0000:00:05.0:pcie004: pciehp_power_off_slot: SLOTCTRL a8 write cmd 400 > > [ 157.224124] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0018 from Slot Status > > [ 157.224194] pciehp 0000:00:05.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 write cmd 300 > > [ 157.224220] pciehp 0000:00:05.0:pcie004: pciehp_check_link_active: lnk_status = 2011 > > [ 157.224223] pciehp 0000:00:05.0:pcie004: Slot(0-3): Link Up > > [ 157.224233] pciehp 0000:00:05.0:pcie004: pciehp_get_power_status: SLOTCTRL a8 value read 7f1 > > [ 157.224281] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > > [ 157.224285] pciehp 0000:00:05.0:pcie004: pciehp_power_on_slot: SLOTCTRL a8 write cmd 0 > > [ 157.224300] pciehp 0000:00:05.0:pcie004: __pciehp_link_set: lnk_ctrl = 0 > > [ 157.224336] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > > [ 157.224339] pciehp 0000:00:05.0:pcie004: pciehp_green_led_blink: SLOTCTRL a8 write cmd 200 > > [ 159.739294] pci 0000:06:00.0 id reading try 50 times with interval 20 ms to get ffffffff > > [ 159.739315] pciehp 0000:00:05.0:pcie004: pciehp_check_link_status: lnk_status = 2011 > > [ 159.739318] pciehp 0000:00:05.0:pcie004: Failed to check link status > > [ 159.739371] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > > [ 159.739394] pciehp 0000:00:05.0:pcie004: pciehp_power_off_slot: SLOTCTRL a8 write cmd 400 > > [ 160.771426] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > > [ 160.771452] pciehp 0000:00:05.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 write cmd 300 > > [ 160.771495] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > > [ 160.771499] pciehp 0000:00:05.0:pcie004: pciehp_set_attention_status: SLOTCTRL a8 write cmd 40 > > [ 160.771535] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status > > [ 160.771539] pciehp 0000:00:05.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 write cmd 300 > > > > After analyzing the log information, it seems that qemu doesn't > > change the Link Status from active to inactive after hot-unplug. > > This results in the abnormal log after the linux kernel commit > > d331710ea78fea merged. > > > > Furthermore, If I hotplug the same virtio-blk disk after hot-unplug, > > the virtio-blk would turn on and then back off. > > > > So this patch set the Link Status inactive after hot-unplug and > > active after hot-plug. > > > > Signed-off-by: Zheng Xiang <zhengxiang9@huawei.com> > > Signed-off-by: Zheng Xiang <xiang.zheng@linaro.org> > > Cc: Wang Haibin <wanghaibin.wang@huawei.com> > > --- > > hw/pci/pcie.c | 12 ++++++++++++ > > 1 file changed, 12 insertions(+) > > > > diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c > > index 6c91bd4..66b73b8 100644 > > --- a/hw/pci/pcie.c > > +++ b/hw/pci/pcie.c > > @@ -345,6 +345,10 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev, > > if (!dev->hotplugged) { > > pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, > > PCI_EXP_SLTSTA_PDS); > > + if (pci_dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) { > > + pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA, > > + PCI_EXP_LNKSTA_DLLLA); > > + } > > return; > > } > > @@ -355,6 +359,10 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev, > > if (pci_get_function_0(pci_dev)) { > > pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, > > PCI_EXP_SLTSTA_PDS); > > + if (pci_dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) { > > + pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA, > > + PCI_EXP_LNKSTA_DLLLA); > > + } > > pcie_cap_slot_event(PCI_DEVICE(hotplug_dev), > > PCI_EXP_HP_EV_PDC | PCI_EXP_HP_EV_ABP); > > } > > @@ -531,6 +539,10 @@ void pcie_cap_slot_write_config(PCIDevice *dev, > > pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA, > > PCI_EXP_SLTSTA_PDS); > > + if (dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) { > > + pci_word_test_and_clear_mask(exp_cap + PCI_EXP_LNKSTA, > > + PCI_EXP_LNKSTA_DLLLA); > > + } > > pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, > > PCI_EXP_SLTSTA_PDC); > > } > > Looks good to me, > > Reviewed-by: Marcel Apfelbaum<marcel.apfelbaum@gmail.com> > Thanks, > Marcel > > Marcel you need to fix your signature. I can't use it without a space before <. Thanks!
On 12/18/18 4:18 AM, Michael S. Tsirkin wrote: > On Wed, Dec 05, 2018 at 08:23:35AM +0200, Marcel Apfelbaum wrote: >> >> On 12/3/18 9:05 AM, Zheng Xiang wrote: >>> When VM boots from the latest version of linux kernel, after >>> hot-unpluging virtio-blk disks which are hotplugged into >>> pcie-root-port, the VM's dmesg log shows: >>> >>> [ 151.046242] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0001 from Slot Status >>> [ 151.046365] pciehp 0000:00:05.0:pcie004: Slot(0-3): Attention button pressed >>> [ 151.046369] pciehp 0000:00:05.0:pcie004: Slot(0-3): Powering off due to button press >>> [ 151.046420] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status >>> [ 151.046425] pciehp 0000:00:05.0:pcie004: pciehp_green_led_blink: SLOTCTRL a8 write cmd 200 >>> [ 151.046464] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status >>> [ 151.046468] pciehp 0000:00:05.0:pcie004: pciehp_set_attention_status: SLOTCTRL a8 write cmd c0 >>> [ 156.163421] pciehp 0000:00:05.0:pcie004: pciehp_get_power_status: SLOTCTRL a8 value read 2f1 >>> [ 156.163427] pciehp 0000:00:05.0:pcie004: pciehp_unconfigure_device: domain:bus:dev = 0000:06:00 >>> [ 156.198736] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status >>> [ 156.198772] pciehp 0000:00:05.0:pcie004: pciehp_power_off_slot: SLOTCTRL a8 write cmd 400 >>> [ 157.224124] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0018 from Slot Status >>> [ 157.224194] pciehp 0000:00:05.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 write cmd 300 >>> [ 157.224220] pciehp 0000:00:05.0:pcie004: pciehp_check_link_active: lnk_status = 2011 >>> [ 157.224223] pciehp 0000:00:05.0:pcie004: Slot(0-3): Link Up >>> [ 157.224233] pciehp 0000:00:05.0:pcie004: pciehp_get_power_status: SLOTCTRL a8 value read 7f1 >>> [ 157.224281] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status >>> [ 157.224285] pciehp 0000:00:05.0:pcie004: pciehp_power_on_slot: SLOTCTRL a8 write cmd 0 >>> [ 157.224300] pciehp 0000:00:05.0:pcie004: __pciehp_link_set: lnk_ctrl = 0 >>> [ 157.224336] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status >>> [ 157.224339] pciehp 0000:00:05.0:pcie004: pciehp_green_led_blink: SLOTCTRL a8 write cmd 200 >>> [ 159.739294] pci 0000:06:00.0 id reading try 50 times with interval 20 ms to get ffffffff >>> [ 159.739315] pciehp 0000:00:05.0:pcie004: pciehp_check_link_status: lnk_status = 2011 >>> [ 159.739318] pciehp 0000:00:05.0:pcie004: Failed to check link status >>> [ 159.739371] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status >>> [ 159.739394] pciehp 0000:00:05.0:pcie004: pciehp_power_off_slot: SLOTCTRL a8 write cmd 400 >>> [ 160.771426] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status >>> [ 160.771452] pciehp 0000:00:05.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 write cmd 300 >>> [ 160.771495] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status >>> [ 160.771499] pciehp 0000:00:05.0:pcie004: pciehp_set_attention_status: SLOTCTRL a8 write cmd 40 >>> [ 160.771535] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot Status >>> [ 160.771539] pciehp 0000:00:05.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 write cmd 300 >>> >>> After analyzing the log information, it seems that qemu doesn't >>> change the Link Status from active to inactive after hot-unplug. >>> This results in the abnormal log after the linux kernel commit >>> d331710ea78fea merged. >>> >>> Furthermore, If I hotplug the same virtio-blk disk after hot-unplug, >>> the virtio-blk would turn on and then back off. >>> >>> So this patch set the Link Status inactive after hot-unplug and >>> active after hot-plug. >>> >>> Signed-off-by: Zheng Xiang <zhengxiang9@huawei.com> >>> Signed-off-by: Zheng Xiang <xiang.zheng@linaro.org> >>> Cc: Wang Haibin <wanghaibin.wang@huawei.com> >>> --- >>> hw/pci/pcie.c | 12 ++++++++++++ >>> 1 file changed, 12 insertions(+) >>> >>> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c >>> index 6c91bd4..66b73b8 100644 >>> --- a/hw/pci/pcie.c >>> +++ b/hw/pci/pcie.c >>> @@ -345,6 +345,10 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev, >>> if (!dev->hotplugged) { >>> pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, >>> PCI_EXP_SLTSTA_PDS); >>> + if (pci_dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) { >>> + pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA, >>> + PCI_EXP_LNKSTA_DLLLA); >>> + } >>> return; >>> } >>> @@ -355,6 +359,10 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev, >>> if (pci_get_function_0(pci_dev)) { >>> pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, >>> PCI_EXP_SLTSTA_PDS); >>> + if (pci_dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) { >>> + pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA, >>> + PCI_EXP_LNKSTA_DLLLA); >>> + } >>> pcie_cap_slot_event(PCI_DEVICE(hotplug_dev), >>> PCI_EXP_HP_EV_PDC | PCI_EXP_HP_EV_ABP); >>> } >>> @@ -531,6 +539,10 @@ void pcie_cap_slot_write_config(PCIDevice *dev, >>> pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA, >>> PCI_EXP_SLTSTA_PDS); >>> + if (dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) { >>> + pci_word_test_and_clear_mask(exp_cap + PCI_EXP_LNKSTA, >>> + PCI_EXP_LNKSTA_DLLLA); >>> + } >>> pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, >>> PCI_EXP_SLTSTA_PDC); >>> } >> Looks good to me, >> >> Reviewed-by: Marcel Apfelbaum<marcel.apfelbaum@gmail.com> >> Thanks, >> Marcel >> >> > Marcel you need to fix your signature. I can't use it without > a space before <. Ooops, sorry, I'll take care of it. Reviewed-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com> Thanks, Marcel > Thanks! >
diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c index 6c91bd4..66b73b8 100644 --- a/hw/pci/pcie.c +++ b/hw/pci/pcie.c @@ -345,6 +345,10 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev, if (!dev->hotplugged) { pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, PCI_EXP_SLTSTA_PDS); + if (pci_dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) { + pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA, + PCI_EXP_LNKSTA_DLLLA); + } return; } @@ -355,6 +359,10 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev, if (pci_get_function_0(pci_dev)) { pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, PCI_EXP_SLTSTA_PDS); + if (pci_dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) { + pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA, + PCI_EXP_LNKSTA_DLLLA); + } pcie_cap_slot_event(PCI_DEVICE(hotplug_dev), PCI_EXP_HP_EV_PDC | PCI_EXP_HP_EV_ABP); } @@ -531,6 +539,10 @@ void pcie_cap_slot_write_config(PCIDevice *dev, pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA, PCI_EXP_SLTSTA_PDS); + if (dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) { + pci_word_test_and_clear_mask(exp_cap + PCI_EXP_LNKSTA, + PCI_EXP_LNKSTA_DLLLA); + } pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA, PCI_EXP_SLTSTA_PDC); }