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Date: Tue, 5 Aug 2008 01:53:22 +0200
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Jesse Barnes <jbarnes@...tuousgeek.org>
Cc: David Miller <davem@...emloft.net>, arekm@...en.pl,
linux-kernel@...r.kernel.org, akpm@...ux-foundation.org
Subject: Re: BUG: scheduling while atomic: ip/23212/0x00000102
On Tuesday, 5 of August 2008, Jesse Barnes wrote:
> On Monday, August 04, 2008 3:10 pm Rafael J. Wysocki wrote:
> > > - pci_read_config_word(tp->pdev,
> > > - pm + PCI_PM_CTRL,
> > > - &power_control);
> > > - power_control |= PCI_PM_CTRL_PME_STATUS;
> > > - power_control &= ~(PCI_PM_CTRL_STATE_MASK);
> > > switch (state) {
> > > case PCI_D0:
> > > - power_control |= 0;
> > > - pci_write_config_word(tp->pdev,
> > > - pm + PCI_PM_CTRL,
> > > - power_control);
> > > - udelay(100); /* Delay after power state change */
> > > + pci_enable_wake(tp->pdev, state, false);
> > > + pci_set_power_state(tp->pdev, PCI_D0);
> >
> > Still, I don't think drivers should access the standard PCI PM registers
> > directly, so perhaps there should be a version of pci_set_power_state()
> > using udelay() instead of msleep() or we can just replace the msleep()
> > in pci_set_power_state() with udelay()?
>
> I think we should get rid of the open coded PCI PM state management, since
> otherwise platform related bugs like the Intel PCIe PM quirk that sets
> pci_pm_d3_delay to 120ms would have to be duplicated around the tree.
>
> That said, waiting for 120ms with a busy wait seems a bit absurd if we can
> avoid it. Either we need to find a way to make drivers only change states
> (which can be very slow) in non-atomic context or we'll need to add a busy
> wait variant of the power state call...
What about this?
It fixes the tg3 issue for me.
---
drivers/net/tg3.c | 19 +++++++++++++++++--
drivers/pci/pci.c | 24 +++++++++++++++---------
include/linux/pci.h | 2 ++
3 files changed, 34 insertions(+), 11 deletions(-)
Index: linux-2.6/drivers/pci/pci.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci.c
+++ linux-2.6/drivers/pci/pci.c
@@ -421,6 +421,7 @@ static inline int platform_pci_sleep_wak
* given PCI device
* @dev: PCI device to handle.
* @state: PCI power state (D0, D1, D2, D3hot) to put the device into.
+ * @delay: if set, time to wait for the device to change the state, in microseconds
*
* RETURN VALUE:
* -EINVAL if the requested state is invalid.
@@ -429,8 +430,8 @@ static inline int platform_pci_sleep_wak
* 0 if device already is in the requested state.
* 0 if device's power state has been successfully changed.
*/
-static int
-pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
+int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state,
+ unsigned int delay)
{
u16 pmcsr;
bool need_restore = false;
@@ -486,12 +487,16 @@ pci_raw_set_power_state(struct pci_dev *
/* enter specified state */
pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, pmcsr);
- /* Mandatory power management transition delays */
- /* see PCI PM 1.1 5.6.1 table 18 */
- if (state == PCI_D3hot || dev->current_state == PCI_D3hot)
- msleep(pci_pm_d3_delay);
- else if (state == PCI_D2 || dev->current_state == PCI_D2)
- udelay(200);
+ if (delay) {
+ udelay(delay);
+ } else {
+ /* Mandatory power management transition delays */
+ /* see PCI PM 1.1 5.6.1 table 18 */
+ if (state == PCI_D3hot || dev->current_state == PCI_D3hot)
+ msleep(pci_pm_d3_delay);
+ else if (state == PCI_D2 || dev->current_state == PCI_D2)
+ udelay(200);
+ }
dev->current_state = state;
@@ -577,7 +582,7 @@ int pci_set_power_state(struct pci_dev *
if (state == PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3))
return 0;
- error = pci_raw_set_power_state(dev, state);
+ error = pci_raw_set_power_state(dev, state, 0);
if (state > PCI_D0 && platform_pci_power_manageable(dev)) {
/* Allow the platform to finalize the transition */
@@ -1941,6 +1946,7 @@ EXPORT_SYMBOL(pci_assign_resource);
EXPORT_SYMBOL(pci_find_parent_resource);
EXPORT_SYMBOL(pci_select_bars);
+EXPORT_SYMBOL(pci_raw_set_power_state);
EXPORT_SYMBOL(pci_set_power_state);
EXPORT_SYMBOL(pci_save_state);
EXPORT_SYMBOL(pci_restore_state);
Index: linux-2.6/include/linux/pci.h
===================================================================
--- linux-2.6.orig/include/linux/pci.h
+++ linux-2.6/include/linux/pci.h
@@ -645,6 +645,8 @@ size_t pci_get_rom_size(void __iomem *ro
/* Power management related routines */
int pci_save_state(struct pci_dev *dev);
int pci_restore_state(struct pci_dev *dev);
+int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state,
+ unsigned int delay);
int pci_set_power_state(struct pci_dev *dev, pci_power_t state);
pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state);
bool pci_pme_capable(struct pci_dev *dev, pci_power_t state);
Index: linux-2.6/drivers/net/tg3.c
===================================================================
--- linux-2.6.orig/drivers/net/tg3.c
+++ linux-2.6/drivers/net/tg3.c
@@ -1979,6 +1979,21 @@ static void tg3_power_down_phy(struct tg
tg3_writephy(tp, MII_BMCR, BMCR_PDOWN);
}
+static int tg3_force_power_state_d0(struct tg3 *tp)
+{
+ int error;
+
+ error = pci_raw_set_power_state(tp->pdev, PCI_D0, 100);
+ if (error)
+ return error;
+
+ /* Switch out of Vaux if it is a NIC */
+ if (tp->tg3_flags2 & TG3_FLG2_IS_NIC)
+ tw32_wait_f(GRC_LOCAL_CTRL, tp->grc_local_ctrl, 100);
+
+ return 0;
+}
+
static int tg3_set_power_state(struct tg3 *tp, pci_power_t state)
{
u32 misc_host_ctrl;
@@ -7690,7 +7705,7 @@ static int tg3_init_hw(struct tg3 *tp, i
int err;
/* Force the chip into D0. */
- err = tg3_set_power_state(tp, PCI_D0);
+ err = tg3_force_power_state_d0(tp);
if (err)
goto out;
@@ -8018,7 +8033,7 @@ static int tg3_open(struct net_device *d
tg3_full_lock(tp, 0);
- err = tg3_set_power_state(tp, PCI_D0);
+ err = tg3_force_power_state_d0(tp);
if (err) {
tg3_full_unlock(tp);
return err;
--
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