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Date: Sun, 7 Dec 2008 22:02:58 +0100
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Greg KH <greg@...ah.com>, Ingo Molnar <mingo@...e.hu>,
Jesse Barnes <jbarnes@...tuousgeek.org>,
Len Brown <lenb@...nel.org>,
LKML <linux-kernel@...r.kernel.org>,
Takashi Iwai <tiwai@...e.de>,
Andrew Morton <akpm@...ux-foundation.org>,
pm list <linux-pm@...ts.linux-foundation.org>
Subject: Re: [PATCH 1/3] PCI: Rework default handling of suspend and resume
On Sunday, 7 of December 2008, Linus Torvalds wrote:
>
> On Sun, 7 Dec 2008, Rafael J. Wysocki wrote:
> >
> > If there is no objection from Jesse and if you don't mind, I'll prepare a
> > version of the $subject patch on top of the patch in your tree and send it to
> > you.
>
> Rafael: there's a bug in your 1/3 patch.
>
> It looks like "pci_save_state()" is currently unhappy with being called
> with interrupts disabled. Or at least "pci_save_pci[ex]_state()" state
> are. They both do a kzalloc(GFP_KERNEL).
>
> So you should change that GFP_KERNEL into a GFP_ATOMIC. Or do something
> more complicated like pre-allocate them during early suspend, but just
> changing it to GFP_ATOMIC seems to be the trivial fix.
>
> I'm not seeing any other issues with saving/restoring things with irq's
> disabled, but people should be on the lookout for details like this.
I overlooked that, sorry.
What about doing the following in addition to patch [1/3]?
Rafael
---
drivers/pci/pci.c | 73 ++++++++++++++++++++++++++++++++++++----------------
drivers/pci/pci.h | 1
drivers/pci/probe.c | 3 ++
3 files changed, 55 insertions(+), 22 deletions(-)
Index: linux-2.6/drivers/pci/probe.c
===================================================================
--- linux-2.6.orig/drivers/pci/probe.c
+++ linux-2.6/drivers/pci/probe.c
@@ -958,6 +958,9 @@ static void pci_init_capabilities(struct
/* MSI/MSI-X list */
pci_msi_init_pci_dev(dev);
+ /* Buffers for saving PCIe and PCI-X capabilities */
+ pci_allocate_cap_save_buffers(dev);
+
/* Power Management */
pci_pm_init(dev);
Index: linux-2.6/drivers/pci/pci.h
===================================================================
--- linux-2.6.orig/drivers/pci/pci.h
+++ linux-2.6/drivers/pci/pci.h
@@ -41,6 +41,7 @@ struct pci_platform_pm_ops {
extern int pci_set_platform_pm(struct pci_platform_pm_ops *ops);
extern void pci_pm_init(struct pci_dev *dev);
+extern void pci_allocate_cap_save_buffers(struct pci_dev *dev);
extern int pci_user_read_config_byte(struct pci_dev *dev, int where, u8 *val);
extern int pci_user_read_config_word(struct pci_dev *dev, int where, u16 *val);
Index: linux-2.6/drivers/pci/pci.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci.c
+++ linux-2.6/drivers/pci/pci.c
@@ -640,19 +640,14 @@ static int pci_save_pcie_state(struct pc
int pos, i = 0;
struct pci_cap_saved_state *save_state;
u16 *cap;
- int found = 0;
pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
if (pos <= 0)
return 0;
save_state = pci_find_saved_cap(dev, PCI_CAP_ID_EXP);
- if (!save_state)
- save_state = kzalloc(sizeof(*save_state) + sizeof(u16) * 4, GFP_KERNEL);
- else
- found = 1;
if (!save_state) {
- dev_err(&dev->dev, "out of memory in pci_save_pcie_state\n");
+ dev_err(&dev->dev, "buffer not found in %s\n", __FUNCTION__);
return -ENOMEM;
}
cap = (u16 *)&save_state->data[0];
@@ -661,9 +656,7 @@ static int pci_save_pcie_state(struct pc
pci_read_config_word(dev, pos + PCI_EXP_LNKCTL, &cap[i++]);
pci_read_config_word(dev, pos + PCI_EXP_SLTCTL, &cap[i++]);
pci_read_config_word(dev, pos + PCI_EXP_RTCTL, &cap[i++]);
- save_state->cap_nr = PCI_CAP_ID_EXP;
- if (!found)
- pci_add_saved_cap(dev, save_state);
+
return 0;
}
@@ -688,30 +681,21 @@ static void pci_restore_pcie_state(struc
static int pci_save_pcix_state(struct pci_dev *dev)
{
- int pos, i = 0;
+ int pos;
struct pci_cap_saved_state *save_state;
- u16 *cap;
- int found = 0;
pos = pci_find_capability(dev, PCI_CAP_ID_PCIX);
if (pos <= 0)
return 0;
save_state = pci_find_saved_cap(dev, PCI_CAP_ID_PCIX);
- if (!save_state)
- save_state = kzalloc(sizeof(*save_state) + sizeof(u16), GFP_KERNEL);
- else
- found = 1;
if (!save_state) {
- dev_err(&dev->dev, "out of memory in pci_save_pcie_state\n");
+ dev_err(&dev->dev, "buffer not found in %s\n", __FUNCTION__);
return -ENOMEM;
}
- cap = (u16 *)&save_state->data[0];
- pci_read_config_word(dev, pos + PCI_X_CMD, &cap[i++]);
- save_state->cap_nr = PCI_CAP_ID_PCIX;
- if (!found)
- pci_add_saved_cap(dev, save_state);
+ pci_read_config_word(dev, pos + PCI_X_CMD, (u16 *)save_state->data);
+
return 0;
}
@@ -1301,6 +1285,51 @@ void pci_pm_init(struct pci_dev *dev)
}
/**
+ * pci_add_save_buffer - allocate buffer for saving given capability registers
+ * @dev: the PCI device
+ * @cap: the capability to allocate the buffer for
+ * @size: requested size of the buffer
+ */
+static int pci_add_cap_save_buffer(
+ struct pci_dev *dev, char cap, unsigned int size)
+{
+ int pos;
+ struct pci_cap_saved_state *save_state;
+
+ pos = pci_find_capability(dev, cap);
+ if (pos <= 0)
+ return 0;
+
+ save_state = kzalloc(sizeof(*save_state) + size, GFP_KERNEL);
+ if (!save_state)
+ return -ENOMEM;
+
+ save_state->cap_nr = cap;
+ pci_add_saved_cap(dev, save_state);
+
+ return 0;
+}
+
+/**
+ * pci_allocate_cap_save_buffers - allocate buffers for saving capabilities
+ * @dev: the PCI device
+ */
+void pci_allocate_cap_save_buffers(struct pci_dev *dev)
+{
+ int error;
+
+ error = pci_add_cap_save_buffer(dev, PCI_CAP_ID_EXP, 4 * sizeof(u16));
+ if (error)
+ dev_err(&dev->dev,
+ "unable to preallocate PCI Express save buffer\n");
+
+ error = pci_add_cap_save_buffer(dev, PCI_CAP_ID_PCIX, sizeof(u16));
+ if (error)
+ dev_err(&dev->dev,
+ "unable to preallocate PCI-X save buffer\n");
+}
+
+/**
* pci_enable_ari - enable ARI forwarding if hardware support it
* @dev: the PCI device
*/
--
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