litmus-rt.git - The LITMUS^RT kernel.

diff options

author	Ilija Hadzic <ihadzic@research.bell-labs.com>	2011-10-31 13:11:57 -0400
committer	Dave Airlie <airlied@redhat.com>	2011-11-11 06:16:30 -0500
commit	a6778e9e7fb57603f15344ceb30098a3f6b7caf4 (patch)
tree	1422443322e6bd119edab9db60dc6ae2e3d3b29f /tools/perf/scripts/python/bin
parent	bfba16582600ab2c75dc39250a2b8f3b2a42da11 (diff)

drm: add some comments to drm_wait_vblank and drm_queue_vblank_event

during the review of the fix for locks problems in drm_wait_vblank, a couple of false concerns were raised about how the drm_vblank_get and drm_vblank_put are used in this function; it turned out that the code is correct and that it cannot be simplified add a few comments to explain non-obvious flows in the code, to prevent "false alarms" in the future v2: incorporate comments received from Daniel Vetter Signed-off-by: Ilija Hadzic <ihadzic@research.bell-labs.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Dave Airlie <airlied@redhat.com>

Diffstat (limited to 'tools/perf/scripts/python/bin')

0 files changed, 0 insertions, 0 deletions

/* * (C) Copyright David Brownell 2000-2002 * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software Foundation, * Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/pci.h> #include <linux/usb.h> #include <asm/io.h> #include <asm/irq.h> #ifdef CONFIG_PPC_PMAC #include <asm/machdep.h> #include <asm/pmac_feature.h> #include <asm/pci-bridge.h> #include <asm/prom.h> #endif #include "usb.h" #include "hcd.h" /* PCI-based HCs are common, but plenty of non-PCI HCs are used too */ /*-------------------------------------------------------------------------*/ /* configure so an HC device and id are always provided */ /* always called with process context; sleeping is OK */ /** * usb_hcd_pci_probe - initialize PCI-based HCDs * @dev: USB Host Controller being probed * @id: pci hotplug id connecting controller to HCD framework * Context: !in_interrupt() * * Allocates basic PCI resources for this USB host controller, and * then invokes the start() method for the HCD associated with it * through the hotplug entry's driver_data. * * Store this function in the HCD's struct pci_driver as probe(). */ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id) { struct hc_driver *driver; struct usb_hcd *hcd; int retval; if (usb_disabled()) return -ENODEV; if (!id) return -EINVAL; driver = (struct hc_driver *)id->driver_data; if (!driver) return -EINVAL; if (pci_enable_device(dev) < 0) return -ENODEV; dev->current_state = PCI_D0; if (!dev->irq) { dev_err(&dev->dev, "Found HC with no IRQ. Check BIOS/PCI %s setup!\n", pci_name(dev)); retval = -ENODEV; goto err1; } hcd = usb_create_hcd(driver, &dev->dev, pci_name(dev)); if (!hcd) { retval = -ENOMEM; goto err1; } if (driver->flags & HCD_MEMORY) { /* EHCI, OHCI */ hcd->rsrc_start = pci_resource_start(dev, 0); hcd->rsrc_len = pci_resource_len(dev, 0); if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len, driver->description)) { dev_dbg(&dev->dev, "controller already in use\n"); retval = -EBUSY; goto err2; } hcd->regs = ioremap_nocache(hcd->rsrc_start, hcd->rsrc_len); if (hcd->regs == NULL) { dev_dbg(&dev->dev, "error mapping memory\n"); retval = -EFAULT; goto err3; } } else { /* UHCI */ int region; for (region = 0; region < PCI_ROM_RESOURCE; region++) { if (!(pci_resource_flags(dev, region) & IORESOURCE_IO)) continue; hcd->rsrc_start = pci_resource_start(dev, region); hcd->rsrc_len = pci_resource_len(dev, region); if (request_region(hcd->rsrc_start, hcd->rsrc_len, driver->description)) break; } if (region == PCI_ROM_RESOURCE) { dev_dbg(&dev->dev, "no i/o regions available\n"); retval = -EBUSY; goto err1; } } pci_set_master(dev); retval = usb_add_hcd(hcd, dev->irq, IRQF_DISABLED | IRQF_SHARED); if (retval != 0) goto err4; return retval; err4: if (driver->flags & HCD_MEMORY) { iounmap(hcd->regs); err3: release_mem_region(hcd->rsrc_start, hcd->rsrc_len); } else release_region(hcd->rsrc_start, hcd->rsrc_len); err2: usb_put_hcd(hcd); err1: pci_disable_device(dev); dev_err(&dev->dev, "init %s fail, %d\n", pci_name(dev), retval); return retval; } EXPORT_SYMBOL_GPL(usb_hcd_pci_probe); /* may be called without controller electrically present */ /* may be called with controller, bus, and devices active */ /** * usb_hcd_pci_remove - shutdown processing for PCI-based HCDs * @dev: USB Host Controller being removed * Context: !in_interrupt() * * Reverses the effect of usb_hcd_pci_probe(), first invoking * the HCD's stop() method. It is always called from a thread * context, normally "rmmod", "apmd", or something similar. * * Store this function in the HCD's struct pci_driver as remove(). */ void usb_hcd_pci_remove(struct pci_dev *dev) { struct usb_hcd *hcd; hcd = pci_get_drvdata(dev); if (!hcd) return; usb_remove_hcd(hcd); if (hcd->driver->flags & HCD_MEMORY) { iounmap(hcd->regs); release_mem_region(hcd->rsrc_start, hcd->rsrc_len); } else { release_region(hcd->rsrc_start, hcd->rsrc_len); } usb_put_hcd(hcd); pci_disable_device(dev); } EXPORT_SYMBOL_GPL(usb_hcd_pci_remove); #ifdef CONFIG_PM /** * usb_hcd_pci_suspend - power management suspend of a PCI-based HCD * @dev: USB Host Controller being suspended * @message: semantics in flux * * Store this function in the HCD's struct pci_driver as suspend(). */ int usb_hcd_pci_suspend(struct pci_dev *dev, pm_message_t message) { struct usb_hcd *hcd; int retval = 0; int has_pci_pm; hcd = pci_get_drvdata(dev); /* Root hub suspend should have stopped all downstream traffic, * and all bus master traffic. And done so for both the interface * and the stub usb_device (which we check here). But maybe it * didn't; writing sysfs power/state files ignores such rules... * * We must ignore the FREEZE vs SUSPEND distinction here, because * otherwise the swsusp will save (and restore) garbage state. */ if (!(hcd->state == HC_STATE_SUSPENDED || hcd->state == HC_STATE_HALT)) return -EBUSY; if (hcd->driver->suspend) { retval = hcd->driver->suspend(hcd, message); suspend_report_result(hcd->driver->suspend, retval); if (retval) goto done; } synchronize_irq(dev->irq); /* FIXME until the generic PM interfaces change a lot more, this * can't use PCI D1 and D2 states. For example, the confusion * between messages and states will need to vanish, and messages * will need to provide a target system state again. * * It'll be important to learn characteristics of the target state, * especially on embedded hardware where the HCD will often be in * charge of an external VBUS power supply and one or more clocks. * Some target system states will leave them active; others won't. * (With PCI, that's often handled by platform BIOS code.) */ /* even when the PCI layer rejects some of the PCI calls * below, HCs can try global suspend and reduce DMA traffic. * PM-sensitive HCDs may already have done this. */ has_pci_pm = pci_find_capability(dev, PCI_CAP_ID_PM); /* Downstream ports from this root hub should already be quiesced, so * there will be no DMA activity. Now we can shut down the upstream * link (except maybe for PME# resume signaling) and enter some PCI * low power state, if the hardware allows. */ if (hcd->state == HC_STATE_SUSPENDED) { /* no DMA or IRQs except when HC is active */ if (dev->current_state == PCI_D0) { pci_save_state(dev); pci_disable_device(dev); } if (message.event == PM_EVENT_FREEZE || message.event == PM_EVENT_PRETHAW) { dev_dbg(hcd->self.controller, "--> no state change\n"); goto done; } if (!has_pci_pm) { dev_dbg(hcd->self.controller, "--> PCI D0/legacy\n"); goto done; } /* NOTE: dev->current_state becomes nonzero only here, and * only for devices that support PCI PM. Also, exiting * PCI_D3 (but not PCI_D1 or PCI_D2) is allowed to reset * some device state (e.g. as part of clock reinit). */ retval = pci_set_power_state(dev, PCI_D3hot); suspend_report_result(pci_set_power_state, retval); if (retval == 0) { int wake = device_can_wakeup(&hcd->self.root_hub->dev); wake = wake && device_may_wakeup(hcd->self.controller); dev_dbg(hcd->self.controller, "--> PCI D3%s\n", wake ? "/wakeup" : ""); /* Ignore these return values. We rely on pci code to * reject requests the hardware can't implement, rather * than coding the same thing. */ (void) pci_enable_wake(dev, PCI_D3hot, wake); (void) pci_enable_wake(dev, PCI_D3cold, wake); } else { dev_dbg(&dev->dev, "PCI D3 suspend fail, %d\n", retval); (void) usb_hcd_pci_resume(dev); } } else if (hcd->state != HC_STATE_HALT) { dev_dbg(hcd->self.controller, "hcd state %d; not suspended\n", hcd->state); WARN_ON(1); retval = -EINVAL; } done: if (retval == 0) { #ifdef CONFIG_PPC_PMAC /* Disable ASIC clocks for USB */ if (machine_is(powermac)) { struct device_node *of_node; of_node = pci_device_to_OF_node(dev); if (of_node) pmac_call_feature(PMAC_FTR_USB_ENABLE, of_node, 0, 0); } #endif } return retval; } EXPORT_SYMBOL_GPL(usb_hcd_pci_suspend); /** * usb_hcd_pci_resume - power management resume of a PCI-based HCD * @dev: USB Host Controller being resumed * * Store this function in the HCD's struct pci_driver as resume(). */ int usb_hcd_pci_resume(struct pci_dev *dev) { struct usb_hcd *hcd; int retval; hcd = pci_get_drvdata(dev); if (hcd->state != HC_STATE_SUSPENDED) { dev_dbg(hcd->self.controller, "can't resume, not suspended!\n"); return 0; } #ifdef CONFIG_PPC_PMAC /* Reenable ASIC clocks for USB */ if (machine_is(powermac)) { struct device_node *of_node; of_node = pci_device_to_OF_node(dev); if (of_node) pmac_call_feature(PMAC_FTR_USB_ENABLE, of_node, 0, 1); } #endif /* NOTE: chip docs cover clean "real suspend" cases (what Linux * calls "standby", "suspend to RAM", and so on). There are also * dirty cases when swsusp fakes a suspend in "shutdown" mode. */ if (dev->current_state != PCI_D0) { #ifdef DEBUG int pci_pm; u16 pmcr; pci_pm = pci_find_capability(dev, PCI_CAP_ID_PM); pci_read_config_word(dev, pci_pm + PCI_PM_CTRL, &pmcr); pmcr &= PCI_PM_CTRL_STATE_MASK; if (pmcr) { /* Clean case: power to USB and to HC registers was * maintained; remote wakeup is easy. */ dev_dbg(hcd->self.controller, "resume from PCI D%d\n", pmcr); } else { /* Clean: HC lost Vcc power, D0 uninitialized * + Vaux may have preserved port and transceiver * state ... for remote wakeup from D3cold * + or not; HCD must reinit + re-enumerate * * Dirty: D0 semi-initialized cases with swsusp * + after BIOS init * + after Linux init (HCD statically linked) */ dev_dbg(hcd->self.controller, "PCI D0, from previous PCI D%d\n", dev->current_state); } #endif /* yes, ignore these results too... */ (void) pci_enable_wake(dev, dev->current_state, 0); (void) pci_enable_wake(dev, PCI_D3cold, 0); } else { /* Same basic cases: clean (powered/not), dirty */ dev_dbg(hcd->self.controller, "PCI legacy resume\n"); } /* NOTE: the PCI API itself is asymmetric here. We don't need to * pci_set_power_state(PCI_D0) since that's part of re-enabling; * but that won't re-enable bus mastering. Yet pci_disable_device() * explicitly disables bus mastering... */ retval = pci_enable_device(dev); if (retval < 0) { dev_err(hcd->self.controller, "can't re-enable after resume, %d!\n", retval); return retval; } pci_set_master(dev); pci_restore_state(dev); clear_bit(HCD_FLAG_SAW_IRQ, &hcd->flags); if (hcd->driver->resume) { retval = hcd->driver->resume(hcd); if (retval) { dev_err(hcd->self.controller, "PCI post-resume error %d!\n", retval); usb_hc_died(hcd); } } return retval; } EXPORT_SYMBOL_GPL(usb_hcd_pci_resume); #endif /* CONFIG_PM */ /** * usb_hcd_pci_shutdown - shutdown host controller * @dev: USB Host Controller being shutdown */ void usb_hcd_pci_shutdown(struct pci_dev *dev) { struct usb_hcd *hcd; hcd = pci_get_drvdata(dev); if (!hcd) return; if (hcd->driver->shutdown) hcd->driver->shutdown(hcd); } EXPORT_SYMBOL_GPL(usb_hcd_pci_shutdown);


context:
space:
mode: