From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: m.kozlov@samsung.com, d.solodkiy@samsung.com,
Evgeny Voevodin <e.voevodin@samsung.com>
Subject: Re: [Qemu-devel] [PATCH 08/15] hw/arm_gic.c: lower IRQ only on changing of enable bit.
Date: Fri, 9 Dec 2011 15:55:01 +0000 [thread overview]
Message-ID: <201112091555.02533.paul@codesourcery.com> (raw)
In-Reply-To: <1323437682-28792-9-git-send-email-e.voevodin@samsung.com>
> In previous version IRQ was lowered every time if enable bits were
> not set. If platform has splitted IRQ source to pass IRQ to two
> identical GICs simultaneously in first of which IRQ passing is
> enabled but in second is disabled, handling IRQ by second GIC would
> lower IRQ previously raised by first GIC.
> Linux kernel v3.0 faces this problem.
> The problem is avoided if IRQ is only lowered as result of
> transitioning enable bits to zeroes.
This is almost certainly wrong. IRQ lines are state based, not event based.
Re-asserting an existing level should always be a no-op.
My guess is your real bug it that your IRQ wiring is broken, and you have
multiple outputs connected to a single input. Don't do that. Ever. If you
need to connent multiple output pins to a single input pin then you need an
explicit device (e.g. an or gate) in between.
Paul
next prev parent reply other threads:[~2011-12-09 15:55 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-09 13:34 [Qemu-devel] [PATCH 00/15 V2] ARM: Samsung Exynos4210-based boards support Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 01/15] ARM: Samsung exynos4210-based boards emulation Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 02/15] ARM: exynos4210: CMU support Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 03/15] ARM: exynos4210: UART support Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 04/15] hw/sysbus.h: Increase maximum number of device IRQs Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 05/15] ARM: exynos4210: IRQ subsystem support Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 06/15] ARM: exynos4210: PWM support Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 07/15] hw/arm_boot.c: Add new secondary CPU bootloader Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 08/15] hw/arm_gic.c: lower IRQ only on changing of enable bit Evgeny Voevodin
2011-12-09 15:55 ` Paul Brook [this message]
2011-12-09 13:34 ` [Qemu-devel] [PATCH 09/15] ARM: exynos4210: MCT support Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 10/15] hw/exynos4210.c: Boot secondary CPU Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 11/15] hw/lan9118: Add basic 16-bit mode support Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 12/15] hw/exynos4210.c: Add LAN support for SMDKC210 Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 13/15] hw/sd.c, hw/sd.h: add receive ready query routine to SD/MMC API Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 14/15] ARM: exynos4210: added SD/MMC host controller Evgeny Voevodin
2011-12-09 13:34 ` [Qemu-devel] [PATCH 15/15] ARM: exynos4210: added display controller implementation Evgeny Voevodin
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