From f6735590e9f441762ab5afeff64ded99e5b19a68 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 27 May 2010 11:21:11 +0900 Subject: PCI aerdrv: fix annoying warnings Some compiler generates following warnings: In function 'aer_isr': warning: 'e_src.id' may be used uninitialized in this function warning: 'e_src.status' may be used uninitialized in this function Avoid status flag "int ret" and return constants instead, so that gcc sees the return value matching "it is initialized" better. Acked-by: Hidetoshi Seto Signed-off-by: Linus Torvalds Signed-off-by: Hidetoshi Seto Signed-off-by: Jesse Barnes --- drivers/pci/pcie/aer/aerdrv_core.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'drivers/pci/pcie') diff --git a/drivers/pci/pcie/aer/aerdrv_core.c b/drivers/pci/pcie/aer/aerdrv_core.c index 8af4f619bba2..fc0b5a93e1de 100644 --- a/drivers/pci/pcie/aer/aerdrv_core.c +++ b/drivers/pci/pcie/aer/aerdrv_core.c @@ -727,20 +727,21 @@ static void aer_isr_one_error(struct pcie_device *p_device, static int get_e_source(struct aer_rpc *rpc, struct aer_err_source *e_src) { unsigned long flags; - int ret = 0; /* Lock access to Root error producer/consumer index */ spin_lock_irqsave(&rpc->e_lock, flags); - if (rpc->prod_idx != rpc->cons_idx) { - *e_src = rpc->e_sources[rpc->cons_idx]; - rpc->cons_idx++; - if (rpc->cons_idx == AER_ERROR_SOURCES_MAX) - rpc->cons_idx = 0; - ret = 1; + if (rpc->prod_idx == rpc->cons_idx) { + spin_unlock_irqrestore(&rpc->e_lock, flags); + return 0; } + + *e_src = rpc->e_sources[rpc->cons_idx]; + rpc->cons_idx++; + if (rpc->cons_idx == AER_ERROR_SOURCES_MAX) + rpc->cons_idx = 0; spin_unlock_irqrestore(&rpc->e_lock, flags); - return ret; + return 1; } /** -- cgit v1.2.2 From 41cd766b065970ff6f6c89dd1cf55fa706c84a3d Mon Sep 17 00:00:00 2001 From: Matthew Garrett Date: Wed, 9 Jun 2010 16:05:07 -0400 Subject: PCI: Don't enable aspm before drivers have had a chance to veto it The aspm code will currently set the configured aspm policy before drivers have had an opportunity to indicate that their hardware doesn't support it. Unfortunately, putting some hardware in L0 or L1 can result in the hardware no longer responding to any requests, even after aspm is disabled. It makes more sense to leave aspm policy at the BIOS defaults at initial setup time, reconfiguring it after pci_enable_device() is called. This allows the driver to blacklist individual devices beforehand. Reviewed-by: Kenji Kaneshige Signed-off-by: Matthew Garrett Signed-off-by: Jesse Barnes --- drivers/pci/pcie/aspm.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'drivers/pci/pcie') diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index be53d98fa384..71222814c1ec 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -588,11 +588,23 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev) * update through pcie_aspm_cap_init(). */ pcie_aspm_cap_init(link, blacklist); - pcie_config_aspm_path(link); /* Setup initial Clock PM state */ pcie_clkpm_cap_init(link, blacklist); - pcie_set_clkpm(link, policy_to_clkpm_state(link)); + + /* + * At this stage drivers haven't had an opportunity to change the + * link policy setting. Enabling ASPM on broken hardware can cripple + * it even before the driver has had a chance to disable ASPM, so + * default to a safe level right now. If we're enabling ASPM beyond + * the BIOS's expectation, we'll do so once pci_enable_device() is + * called. + */ + if (aspm_policy != POLICY_POWERSAVE) { + pcie_config_aspm_path(link); + pcie_set_clkpm(link, policy_to_clkpm_state(link)); + } + unlock: mutex_unlock(&aspm_lock); out: -- cgit v1.2.2 From ea5f9fc5899660dd26c1ccf3fab183bd041140ee Mon Sep 17 00:00:00 2001 From: Matthew Garrett Date: Tue, 22 Jun 2010 17:03:03 -0400 Subject: PCI: Default PCIe ASPM control to on and require !EMBEDDED to disable The CONFIG_PCIEASPM option is confusing and potentially dangerous. ASPM is a hardware mediated feature rather than one under direct OS control, and even if the config option is disabled the system firmware may have turned on ASPM on various bits of hardware. This can cause problems later - various hardware that claims to support ASPM does a poor job of it and may hang or cause other difficulties. The kernel is able to recognise this in many cases and disable the ASPM functionality, but only if CONFIG_PCIEASPM is enabled. Given that in its default configuration this option will either leave the hardware as it was originally or disable hardware functionality that may cause problems, it should by default y. The only reason to disable it ought to be to reduce code size, so make it dependent on CONFIG_EMBEDDED. Signed-off-by: Matthew Garrett Cc: lrodriguez@atheros.com Cc: maximlevitsky@gmail.com Signed-off-by: Jesse Barnes --- drivers/pci/pcie/Kconfig | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) (limited to 'drivers/pci/pcie') diff --git a/drivers/pci/pcie/Kconfig b/drivers/pci/pcie/Kconfig index b8b494b3e0d0..dda70981b7a6 100644 --- a/drivers/pci/pcie/Kconfig +++ b/drivers/pci/pcie/Kconfig @@ -31,14 +31,22 @@ source "drivers/pci/pcie/aer/Kconfig" # PCI Express ASPM # config PCIEASPM - bool "PCI Express ASPM support(Experimental)" - depends on PCI && EXPERIMENTAL && PCIEPORTBUS - default n + bool "PCI Express ASPM control" if EMBEDDED + depends on PCI && PCIEPORTBUS + default y help - This enables PCI Express ASPM (Active State Power Management) and - Clock Power Management. ASPM supports state L0/L0s/L1. + This enables OS control over PCI Express ASPM (Active State + Power Management) and Clock Power Management. ASPM supports + state L0/L0s/L1. - When in doubt, say N. + ASPM is initially set up the the firmware. With this option enabled, + Linux can modify this state in order to disable ASPM on known-bad + hardware or configurations and enable it when known-safe. + + ASPM can be disabled or enabled at runtime via + /sys/module/pcie_aspm/parameters/policy + + When in doubt, say Y. config PCIEASPM_DEBUG bool "Debug PCI Express ASPM" depends on PCIEASPM -- cgit v1.2.2