From ebfc5b802fa76baeb4371311ff9fc27a2258d90d Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 15 Apr 2012 21:40:40 +0200 Subject: PCI: Fix regression in pci_restore_state(), v3 Commit 26f41062f28d ("PCI: check for pci bar restore completion and retry") attempted to address problems with PCI BAR restoration on systems where FLR had not been completed before pci_restore_state() was called, but it did that in an utterly wrong way. First off, instead of retrying the writes for the BAR registers only, it did that for all of the PCI config space of the device, including the status register (whose value after the write quite obviously need not be the same as the written one). Second, it added arbitrary delay to pci_restore_state() even for systems where the PCI config space restoration was successful at first attempt. Finally, the mdelay(10) it added to every iteration of the writing loop was way too much of a delay for any reasonable device. All of this actually caused resume failures for some devices on Mikko's system. To fix the regression, make pci_restore_state() only retry the writes for BAR registers and only wait if the first read from the register doesn't return the written value. Additionaly, make it wait for 1 ms, instead of 10 ms, after every failing attempt to write into config space. Reported-by: Mikko Vinni Signed-off-by: Rafael J. Wysocki Signed-off-by: Linus Torvalds --- drivers/pci/pci.c | 57 +++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 39 insertions(+), 18 deletions(-) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 815674415267..d20f1334792b 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -967,16 +967,47 @@ pci_save_state(struct pci_dev *dev) return 0; } +static void pci_restore_config_dword(struct pci_dev *pdev, int offset, + u32 saved_val, int retry) +{ + u32 val; + + pci_read_config_dword(pdev, offset, &val); + if (val == saved_val) + return; + + for (;;) { + dev_dbg(&pdev->dev, "restoring config space at offset " + "%#x (was %#x, writing %#x)\n", offset, val, saved_val); + pci_write_config_dword(pdev, offset, saved_val); + if (retry-- <= 0) + return; + + pci_read_config_dword(pdev, offset, &val); + if (val == saved_val) + return; + + mdelay(1); + } +} + +static void pci_restore_config_space(struct pci_dev *pdev, int start, int end, + int retry) +{ + int index; + + for (index = end; index >= start; index--) + pci_restore_config_dword(pdev, 4 * index, + pdev->saved_config_space[index], + retry); +} + /** * pci_restore_state - Restore the saved state of a PCI device * @dev: - PCI device that we're dealing with */ void pci_restore_state(struct pci_dev *dev) { - int i; - u32 val; - int tries; - if (!dev->state_saved) return; @@ -984,24 +1015,14 @@ void pci_restore_state(struct pci_dev *dev) pci_restore_pcie_state(dev); pci_restore_ats_state(dev); + pci_restore_config_space(dev, 10, 15, 0); /* * The Base Address register should be programmed before the command * register(s) */ - for (i = 15; i >= 0; i--) { - pci_read_config_dword(dev, i * 4, &val); - tries = 10; - while (tries && val != dev->saved_config_space[i]) { - dev_dbg(&dev->dev, "restoring config " - "space at offset %#x (was %#x, writing %#x)\n", - i, val, (int)dev->saved_config_space[i]); - pci_write_config_dword(dev,i * 4, - dev->saved_config_space[i]); - pci_read_config_dword(dev, i * 4, &val); - mdelay(10); - tries--; - } - } + pci_restore_config_space(dev, 4, 9, 10); + pci_restore_config_space(dev, 0, 3, 0); + pci_restore_pcix_state(dev); pci_restore_msi_state(dev); pci_restore_iov_state(dev); -- cgit v1.2.3-70-g09d2 From a6cb9ee7cabe68002c3f2ab07224ea27d2617cf1 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 16 Apr 2012 23:07:50 +0200 Subject: PCI: Retry BARs restoration for Type 0 headers only Some shortcomings introduced into pci_restore_state() by commit 26f41062f28d ("PCI: check for pci bar restore completion and retry") have been fixed by recent commit ebfc5b802fa76 ("PCI: Fix regression in pci_restore_state(), v3"), but that commit treats all PCI devices as those with Type 0 configuration headers. That is not entirely correct, because Type 1 and Type 2 headers have different layouts. In particular, the area occupied by BARs in Type 0 config headers contains the secondary status register in Type 1 ones and it doesn't make sense to retry the restoration of that register even if the value read back from it after a write is not the same as the written one (it very well may be different). For this reason, make pci_restore_state() only retry the restoration of BARs for Type 0 config headers. This effectively makes it behave as before commit 26f41062f28d for all header types except for Type 0. Tested-by: Mikko Vinni Signed-off-by: Rafael J. Wysocki Signed-off-by: Linus Torvalds --- drivers/pci/pci.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index d20f1334792b..111569ccab43 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -991,8 +991,8 @@ static void pci_restore_config_dword(struct pci_dev *pdev, int offset, } } -static void pci_restore_config_space(struct pci_dev *pdev, int start, int end, - int retry) +static void pci_restore_config_space_range(struct pci_dev *pdev, + int start, int end, int retry) { int index; @@ -1002,6 +1002,18 @@ static void pci_restore_config_space(struct pci_dev *pdev, int start, int end, retry); } +static void pci_restore_config_space(struct pci_dev *pdev) +{ + if (pdev->hdr_type == PCI_HEADER_TYPE_NORMAL) { + pci_restore_config_space_range(pdev, 10, 15, 0); + /* Restore BARs before the command register. */ + pci_restore_config_space_range(pdev, 4, 9, 10); + pci_restore_config_space_range(pdev, 0, 3, 0); + } else { + pci_restore_config_space_range(pdev, 0, 15, 0); + } +} + /** * pci_restore_state - Restore the saved state of a PCI device * @dev: - PCI device that we're dealing with @@ -1015,13 +1027,7 @@ void pci_restore_state(struct pci_dev *dev) pci_restore_pcie_state(dev); pci_restore_ats_state(dev); - pci_restore_config_space(dev, 10, 15, 0); - /* - * The Base Address register should be programmed before the command - * register(s) - */ - pci_restore_config_space(dev, 4, 9, 10); - pci_restore_config_space(dev, 0, 3, 0); + pci_restore_config_space(dev); pci_restore_pcix_state(dev); pci_restore_msi_state(dev); -- cgit v1.2.3-70-g09d2