On Wed, Apr 15, 2015 at 12:01 PM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > On Wednesday, April 15, 2015 05:36:42 PM Rafael J. Wysocki wrote: >> On Apr 15, 2015 3:16 PM, "Rafael J. Wysocki" <rafael@xxxxxxxxxx> wrote: >> > >> > On Wed, Apr 15, 2015 at 2:55 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> >> wrote: >> > > On Tue, Apr 14, 2015 at 8:03 PM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> >> wrote: >> > >> On Tuesday, April 14, 2015 12:28:12 PM Henrique de Moraes Holschuh >> wrote: >> > >>> On Mon, Apr 13, 2015, at 11:23, Rafael J. Wysocki wrote: >> > >>> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> >> > >>> > >> > >>> > Refine the mechanism introduced by commit f244d8b623da (ACPIPHP / >> radeon >> > >>> > / nouveau: Fix VGA switcheroo problem related to hotplug) to >> propagate >> > >>> > the ignore_hotplug setting of the device to its parent bridge in >> case >> > >>> > hotplug notifications related to the graphics adapter switching are >> > >>> > given for the bridge rather than for the device itself (the need to >> > >>> > be ignored in both cases). >> > >>> >> > >>> I do apologise if this is a stupid question, but is there any chance >> the >> > >>> bridge will be connected to other devices that do require hotplug >> handling, >> > >>> and not just to the GPU? >> > >> >> > >> The bridge is actually a downstream PCIe port holding the GPU, so no. >> :-) >> > > >> > > When radeon/nouveau call pci_ignore_hotplug(), that's the case, but in >> > > general all we know is that pci_ignore_hotplug() receives a PCI >> > > device. We don't know whether it's PCI or PCIe. In the hotplug >> > > topologies I'm familiar with, a bridge only leads to one hot-pluggable >> > > slot, but I don't remember anything that would guarantee that. For >> > > PCIe, I think there can only be one slot, but for PCI I would think it >> > > possible to have one bridge leading to several hotpluggable slots, >> > > with the hotplug controller(s) being separate from the bridge. >> > >> > Realistically, the switcheroo people are the only users of >> > pci_ignore_hotplug() today and if somebody wants the hotplug events to >> > be ignored for him and perhaps not for someone else on the same >> > bridge, then something is seriously broken about that system anyway. >> >> There may be a problem if somebody *already* calls this function for the >> parent bridge (which some callers do ISTR) in which case the setting will >> be propagated unnecessarily. >> >> That said, since all of the existing callers of pci_ignore_hotplug() appear >> to need to set the flag for the parent too, IMO it's better to put that >> logic into the interface instead of duplicating it in the callers. So, why >> don't we add a second argument indicating whether or not to propagate the >> setting? > > My previous message didn't seem to reach the mailing lists, so above is a > quote from it and below is a new version of the patch with the additional > argument to pci_ignore_hotplug(). I can't remember why you added the "propagate" argument. Both of the existing callers supply "true". How would a new caller decide whether to supply "true" or "false"? The question of whether hotplug notifications go to the device or the bridge seems like a property of the platform/ACPI design that the driver wouldn't know about. For pciehp, the notification always goes to the bridge, and we check all the devices on the secondary bus for "ignore_hotplug". If it's feasible, it would be nice if acpiphp could use a similar design that doesn't require the propagation. That would reduce code differences and also remove a little ambiguity about what "bridge->ignore_hotplug" means (does it mean "ignore hotplug of devices below the bridge" or "ignore hotplug of this bridge"?) > --- > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > Subject: PCI / hotplug: Propagate the "ignore hotplug" setting to parent > > Refine the mechanism introduced by commit f244d8b623da (ACPIPHP / radeon > / nouveau: Fix VGA switcheroo problem related to hotplug) to optionally > propagate the ignore_hotplug setting of the device to its parent bridge > in case hotplug notifications related to the graphics adapter switching > are given for the bridge rather than for the device itself (the need to > be ignored in both cases). > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=61891 > Link: https://bugs.freedesktop.org/show_bug.cgi?id=88927 > Reported-by: tiagdtd-lava <tiagdtd-lava@xxxxxxxx> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > --- > drivers/gpu/drm/nouveau/nouveau_drm.c | 2 +- > drivers/gpu/drm/radeon/radeon_drv.c | 2 +- > drivers/pci/pci.c | 16 ++++++++++++++++ > include/linux/pci.h | 6 +----- > 4 files changed, 19 insertions(+), 7 deletions(-) > > Index: linux-pm/drivers/pci/pci.c > =================================================================== > --- linux-pm.orig/drivers/pci/pci.c > +++ linux-pm/drivers/pci/pci.c > @@ -4319,6 +4319,22 @@ bool pci_device_is_present(struct pci_de > } > EXPORT_SYMBOL_GPL(pci_device_is_present); > > +/** > + * pci_ignore_hotplug - Ignore subsequent hotplug notifies for this device. > + * @dev: Target device. > + * @propagate: Whether or not to ignore hotplug notifies for the parent bridge. > + */ > +void pci_ignore_hotplug(struct pci_dev *dev, bool propagate) > +{ > + struct pci_dev *bridge = dev->bus->self; > + > + dev->ignore_hotplug = 1; > + /* Propagate the "ignore hotplug" setting to the parent bridge. */ > + if (bridge && propagate) > + bridge->ignore_hotplug = 1; > +} > +EXPORT_SYMBOL_GPL(pci_ignore_hotplug); > + > #define RESOURCE_ALIGNMENT_PARAM_SIZE COMMAND_LINE_SIZE > static char resource_alignment_param[RESOURCE_ALIGNMENT_PARAM_SIZE] = {0}; > static DEFINE_SPINLOCK(resource_alignment_lock); > Index: linux-pm/include/linux/pci.h > =================================================================== > --- linux-pm.orig/include/linux/pci.h > +++ linux-pm/include/linux/pci.h > @@ -1002,6 +1002,7 @@ int __must_check pci_assign_resource(str > int __must_check pci_reassign_resource(struct pci_dev *dev, int i, resource_size_t add_size, resource_size_t align); > int pci_select_bars(struct pci_dev *dev, unsigned long flags); > bool pci_device_is_present(struct pci_dev *pdev); > +void pci_ignore_hotplug(struct pci_dev *dev, bool propagate); > > /* ROM control related routines */ > int pci_enable_rom(struct pci_dev *pdev); > @@ -1039,11 +1040,6 @@ bool pci_dev_run_wake(struct pci_dev *de > bool pci_check_pme_status(struct pci_dev *dev); > void pci_pme_wakeup_bus(struct pci_bus *bus); > > -static inline void pci_ignore_hotplug(struct pci_dev *dev) > -{ > - dev->ignore_hotplug = 1; > -} > - > static inline int pci_enable_wake(struct pci_dev *dev, pci_power_t state, > bool enable) > { > Index: linux-pm/drivers/gpu/drm/nouveau/nouveau_drm.c > =================================================================== > --- linux-pm.orig/drivers/gpu/drm/nouveau/nouveau_drm.c > +++ linux-pm/drivers/gpu/drm/nouveau/nouveau_drm.c > @@ -731,7 +731,7 @@ nouveau_pmops_runtime_suspend(struct dev > ret = nouveau_do_suspend(drm_dev, true); > pci_save_state(pdev); > pci_disable_device(pdev); > - pci_ignore_hotplug(pdev); > + pci_ignore_hotplug(pdev, true); > pci_set_power_state(pdev, PCI_D3cold); > drm_dev->switch_power_state = DRM_SWITCH_POWER_DYNAMIC_OFF; > return ret; > Index: linux-pm/drivers/gpu/drm/radeon/radeon_drv.c > =================================================================== > --- linux-pm.orig/drivers/gpu/drm/radeon/radeon_drv.c > +++ linux-pm/drivers/gpu/drm/radeon/radeon_drv.c > @@ -453,7 +453,7 @@ static int radeon_pmops_runtime_suspend( > ret = radeon_suspend_kms(drm_dev, false, false); > pci_save_state(pdev); > pci_disable_device(pdev); > - pci_ignore_hotplug(pdev); > + pci_ignore_hotplug(pdev, true); > pci_set_power_state(pdev, PCI_D3cold); > drm_dev->switch_power_state = DRM_SWITCH_POWER_DYNAMIC_OFF; > > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
