This is a note to let you know that I've just added the patch titled MIPS: Octeon: Remove udelay() causing huge IRQ latency to the 4.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mips-octeon-remove-udelay-causing-huge-irq-latency.patch and it can be found in the queue-4.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From ralf@xxxxxxxxxxxxxx Fri May 8 16:24:52 2015 From: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Date: Wed, 18 Mar 2015 14:05:21 +0100 Subject: MIPS: Octeon: Remove udelay() causing huge IRQ latency To: stable@xxxxxxxxxxxxxxx Message-ID: <0d6db65f5dd6fb417f1f45bac283d0e23814fe34.1431087908.git.ralf@xxxxxxxxxxxxxx> From: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx> Commit 73bf3c2a500b2db8ac966469591196bf55afb409 upstream. udelay() in PCI/PCIe read/write callbacks cause 30ms IRQ latency on Octeon platforms because these operations are called from PCI_OP_READ() and PCI_OP_WRITE() under raw_spin_lock_irqsave(). Signed-off-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxx Cc: David Daney <ddaney@xxxxxxxxxx> Cc: Rob Herring <robh@xxxxxxxxxx> Cc: Jiri Kosina <jkosina@xxxxxxx> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: Masanari Iida <standby24x7@xxxxxxxxx> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Cc: Mathias <mathias.rulf@xxxxxxxxx> Patchwork: https://patchwork.linux-mips.org/patch/9576/ Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/mips/include/asm/octeon/pci-octeon.h | 3 --- arch/mips/pci/pci-octeon.c | 6 ------ arch/mips/pci/pcie-octeon.c | 8 -------- 3 files changed, 17 deletions(-) --- a/arch/mips/include/asm/octeon/pci-octeon.h +++ b/arch/mips/include/asm/octeon/pci-octeon.h @@ -11,9 +11,6 @@ #include <linux/pci.h> -/* Some PCI cards require delays when accessing config space. */ -#define PCI_CONFIG_SPACE_DELAY 10000 - /* * The physical memory base mapped by BAR1. 256MB at the end of the * first 4GB. --- a/arch/mips/pci/pci-octeon.c +++ b/arch/mips/pci/pci-octeon.c @@ -271,9 +271,6 @@ static int octeon_read_config(struct pci pci_addr.s.func = devfn & 0x7; pci_addr.s.reg = reg; -#if PCI_CONFIG_SPACE_DELAY - udelay(PCI_CONFIG_SPACE_DELAY); -#endif switch (size) { case 4: *val = le32_to_cpu(cvmx_read64_uint32(pci_addr.u64)); @@ -308,9 +305,6 @@ static int octeon_write_config(struct pc pci_addr.s.func = devfn & 0x7; pci_addr.s.reg = reg; -#if PCI_CONFIG_SPACE_DELAY - udelay(PCI_CONFIG_SPACE_DELAY); -#endif switch (size) { case 4: cvmx_write64_uint32(pci_addr.u64, cpu_to_le32(val)); --- a/arch/mips/pci/pcie-octeon.c +++ b/arch/mips/pci/pcie-octeon.c @@ -1762,14 +1762,6 @@ static int octeon_pcie_write_config(unsi default: return PCIBIOS_FUNC_NOT_SUPPORTED; } -#if PCI_CONFIG_SPACE_DELAY - /* - * Delay on writes so that devices have time to come up. Some - * bridges need this to allow time for the secondary busses to - * work - */ - udelay(PCI_CONFIG_SPACE_DELAY); -#endif return PCIBIOS_SUCCESSFUL; } Patches currently in stable-queue which might be from ralf@xxxxxxxxxxxxxx are queue-4.0/mips-octeon-remove-udelay-causing-huge-irq-latency.patch queue-4.0/mips-makefile-fix-mips-ase-detection-code.patch queue-4.0/mips-r4kcache-use-correct-base-register-for-mips-r6-cache-flushes.patch queue-4.0/mips-fix-cpu_has_mips_r2_exec_hazard.patch queue-4.0/mips-ralink-fix-bad-config-symbol-in-pci-makefile.patch queue-4.0/revert-mips-remove-race-window-in-page-fault-handling.patch queue-4.0/mips-fix-race-condition-in-lazy-cache-flushing.patch queue-4.0/mips-bcm63xx-move-bcm63xx_gpio_init-to-bcm63xx_register_devices.patch queue-4.0/mips-octeon-delete-override-of-cpu_has_mips_r2_exec_hazard.patch queue-4.0/mips-asm-spinlock-fix-addiu-instruction-for-r10000_llsc_war-case.patch queue-4.0/mips-kconfig-disable-smp-cps-for-64-bit.patch queue-4.0/mips-bcm47xx-fix-detecting-microsoft-mn-700-asus-wl500g.patch queue-4.0/mips-octeon-use-correct-csr-to-soft-reset.patch queue-4.0/revert-mips-avoid-pipeline-stalls-on-some-mips32r2-cores.patch queue-4.0/mips-octeon-dma-octeon-fix-ohci-usb-config-check.patch queue-4.0/mips-octeon-fix-pci-interrupt-mapping-for-d-link-dsr-1000n.patch queue-4.0/mips-kconfig-fix-typo-for-the-r2-to-r6-emulator-kernel-parameter.patch queue-4.0/ssb-fix-kconfig-dependencies.patch queue-4.0/mips-kernel-entry.s-set-correct-isa-level-for-mips_ihb.patch queue-4.0/mips-netlogic-fix-for-sata-phy-init.patch queue-4.0/mips-ralink-add-missing-symbol-for-ralink_ill_acc.patch queue-4.0/mips-asm-elf-set-o32-default-fpu-flags.patch queue-4.0/mips-smp-cps-cpu_set-fpu-mask-if-fpu-present.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html