98 lines
5.3 KiB
Diff
98 lines
5.3 KiB
Diff
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From 4bfd40ed0046299e4a5ffba31bfbbcc39cf74e03 Mon Sep 17 00:00:00 2001
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From: Marc Zyngier <marc.zyngier@arm.com>
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Date: Thu, 23 Oct 2014 17:49:30 +0100
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Subject: [PATCH] AHCI: Fix threaded interrupt setup
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Commit 18dcf433f3de (AHCI: Optimize single IRQ interrupt processing)
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switched the single IRQ case of the AHCI driver to use threaded
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threaded interrupts.
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During this conversion, only the IRQF_SHARED flag was provided. The net
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effect of this in the presence of level interrupts is that the
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interrupt will not be masked during the execution of the treaded
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handler, leading to a screaming interrupt if the thread is not
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scheduled quickly enough, specially in error conditions:
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[ 2.728051] ahci-sunxi 1c18000.sata: controller can't do PMP, turning off CAP_PMP
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[ 2.735578] ahci-sunxi 1c18000.sata: SSS flag set, parallel bus scan disabled
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[ 2.742792] ahci-sunxi 1c18000.sata: AHCI 0001.0100 32 slots 1 ports 3 Gbps 0x1 impl platform mode
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[ 2.751789] ahci-sunxi 1c18000.sata: flags: ncq sntf stag pm led clo only pio slum part ccc
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[ 2.761539] scsi host0: ahci_platform
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[ 2.765754] ata1: SATA max UDMA/133 mmio [mem 0x01c18000-0x01c18fff] port 0x100 irq 88
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[...]
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[ 3.127977] ata1: SATA link down (SStatus 0 SControl 300)
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[...]
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[ 3.162035] Waiting for root device /dev/sda1...
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[ 3.163700] random: nonblocking pool is initialized
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[ 3.326593] irq 88: nobody cared (try booting with the "irqpoll" option)
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[ 3.333296] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.18.0-rc1+ #3077
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[ 3.339936] [<c002b318>] (unwind_backtrace) from [<c0026980>] (show_stack+0x20/0x24)
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[ 3.347681] [<c0026980>] (show_stack) from [<c067dd18>] (dump_stack+0x9c/0xd4)
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[ 3.354904] [<c067dd18>] (dump_stack) from [<c007ac08>] (__report_bad_irq+0x38/0xd4)
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[ 3.362643] [<c007ac08>] (__report_bad_irq) from [<c007b1dc>] (note_interrupt+0x280/0x2d0)
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[ 3.370903] [<c007b1dc>] (note_interrupt) from [<c0078a70>] (handle_irq_event_percpu+0x210/0x27c)
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[ 3.379771] [<c0078a70>] (handle_irq_event_percpu) from [<c0078b28>] (handle_irq_event+0x4c/0x6c)
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[ 3.388636] [<c0078b28>] (handle_irq_event) from [<c007b860>] (handle_fasteoi_irq+0xbc/0x1a0)
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[ 3.397156] [<c007b860>] (handle_fasteoi_irq) from [<c0077f5c>] (generic_handle_irq+0x3c/0x4c)
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[ 3.405764] [<c0077f5c>] (generic_handle_irq) from [<c0078220>] (__handle_domain_irq+0x6c/0xb4)
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[ 3.414456] [<c0078220>] (__handle_domain_irq) from [<c0008754>] (gic_handle_irq+0x34/0x6c)
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[ 3.422802] [<c0008754>] (gic_handle_irq) from [<c0027540>] (__irq_svc+0x40/0x74)
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[ 3.430274] Exception stack(0xc09c1df8 to 0xc09c1e40)
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[ 3.435321] 1de0: 00000001 c0a27ec0
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[ 3.443491] 1e00: 00000000 00000000 c09c0028 0000001e 00000282 00000000 ee00c400 c0a239f8
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[ 3.451660] 1e20: c09c0000 c09c1ea4 c0a27ec0 c09c1e40 00200000 c003c7cc 20000113 ffffffff
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[ 3.459835] [<c0027540>] (__irq_svc) from [<c003c7cc>] (__do_softirq+0xbc/0x34c)
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[ 3.467229] [<c003c7cc>] (__do_softirq) from [<c003cd44>] (irq_exit+0xbc/0x104)
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[ 3.474536] [<c003cd44>] (irq_exit) from [<c0078224>] (__handle_domain_irq+0x70/0xb4)
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[ 3.482362] [<c0078224>] (__handle_domain_irq) from [<c0008754>] (gic_handle_x74)
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[ 3.498169] Exception stack(0xc09c1f10 to 0xc09c1f58)
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[ 3.503216] 1f00: ee7ca310 00000000 00000ab4 c0035560
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[ 3.511386] 1f20: c09c0000 00000000 c0a23f84 c09c8474 c09c84bc c09c0000 c0688bf8 c09c1f64
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[ 3.519554] 1f40: c09c1f68 c09c1f58 c00235d8 c00235dc 60000113 ffffffff
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[ 3.526165] [<c0027540>] (__irq_svc) from [<c00235dc>] (arch_cpu_idle+0x48/0x4c)
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[ 3.533557] [<c00235dc>] (arch_cpu_idle) from [<c00701fc>] (cpu_startup_entry+0x13c/0x27c)
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[ 3.541816] [<c00701fc>] (cpu_startup_entry) from [<c067af1c>] (rest_init+0x94/0x98)
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[ 3.549557] [<c067af1c>] (rest_init) from [<c093dd38>] (start_kernel+0x3f0/0x3fc)
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[ 3.557036] [<c093dd38>] (start_kernel) from [<40008084>] (0x40008084)
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[ 3.563555] handlers:
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[ 3.565830] [<c03a1a80>] ahci_single_irq_intr threaded [<c03a223c>] ahci_thread_fn
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[ 3.573415] Disabling IRQ #88
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[ 3.576532] ata1: exception Emask 0x10 SAct 0x0 SErr 0x4050002 action 0xe frozen
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[ 3.583977] ata1: irq_stat 0x00400040, connection status changed
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[ 3.590006] ata1: SError: { RecovComm PHYRdyChg CommWake DevExch }
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[ 3.596209] ata1: hard resetting link
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[...]
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Not good. The culprit is a missing IRQF_ONESHOT flag, which addition
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solves the problem entierly. The number of interrupts drops radically:
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[Booting Debian Jessie to a prompt]
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Before fix:
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88: 3562 0 GIC 88 ahci-sunxi
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After fix:
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88: 1992 0 GIC 88 ahci-sunxi
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Tested on a A20 board (ahci-sunxi).
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Cc: Alexander Gordeev <agordeev@redhat.com>
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Cc: Tejun Heo <tj@kernel.org>
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Cc: linux-ide@vger.kernel.org
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Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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---
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drivers/ata/libahci.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
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index 5eb61c9..49c649f 100644
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--- a/drivers/ata/libahci.c
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+++ b/drivers/ata/libahci.c
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@@ -2492,7 +2492,7 @@ static int ahci_host_activate_single_irq(struct ata_host *host, int irq,
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return rc;
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rc = devm_request_threaded_irq(host->dev, irq, ahci_single_irq_intr,
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- ahci_thread_fn, IRQF_SHARED,
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+ ahci_thread_fn, IRQF_SHARED | IRQF_ONESHOT,
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dev_driver_string(host->dev), host);
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if (rc)
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return rc;
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