Re: ACPI resource change triggers loss of serial ports
From: Rafael J. Wysocki
Date: Mon Jul 07 2014 - 08:39:22 EST
On Thursday, June 19, 2014 11:41:30 AM Andy Whitcroft wrote:
> The recently merged change (in v3.14-rc6) to ACPI resource detection
> (below) causes all zero length ACPI resources to be elided from the table:
>
> commit b355cee88e3b1a193f0e9a81db810f6f83ad728b
> Author: Zhang Rui <rui.zhang@xxxxxxxxx>
> Date: Thu Feb 27 11:37:15 2014 +0800
>
> ACPI / resources: ignore invalid ACPI device resources
>
> This change has caused a regression in (at least) serial port detection
> for a number of machines (see LP#1313981 [1]). These seem to represent
> their IO regions (presumably incorrectly) as a zero length region.
> Reverting the above commit restores these serial devices.
>
> For Zhang's case I wonder if this check could be tightened up to cover
> only the zero base, something like the (untested) patch below.
>
> -apw
>
> [1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1313981
I'm going to queue up the patch below for 3.16.
Rui, can you please have a look at this and let me know if there's
anything wrong with it?
Rafael
> From e5211c68278387ef65e483bcfedd5581a79ec783 Mon Sep 17 00:00:00 2001
> From: Andy Whitcroft <apw@xxxxxxxxxxxxx>
> Date: Thu, 19 Jun 2014 11:19:16 +0100
> Subject: [PATCH] ACPI / Resources: only reject zero length resources based at
> address zero
>
> The recently merged change (in v3.14-rc6) to ACPI resource detection
> (below) causes all zero length ACPI resources to be elided from the
> table:
>
> commit b355cee88e3b1a193f0e9a81db810f6f83ad728b
> Author: Zhang Rui <rui.zhang@xxxxxxxxx>
> Date: Thu Feb 27 11:37:15 2014 +0800
>
> ACPI / resources: ignore invalid ACPI device resources
>
> This change has caused a regression in (at least) serial port detection
> for a number of machines (see LP#1313981 [1]). These seem to represent
> their IO regions (presumably incorrectly) as a zero length region.
> Reverting the above commit restores these serial devices.
>
> Only elide zero length resources which lie at address 0.
>
> Signed-off-by: Andy Whitcroft <apw@xxxxxxxxxxxxx>
> ---
> drivers/acpi/resource.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
> index 0bdacc5..2ba8f02 100644
> --- a/drivers/acpi/resource.c
> +++ b/drivers/acpi/resource.c
> @@ -77,7 +77,7 @@ bool acpi_dev_resource_memory(struct acpi_resource *ares, struct resource *res)
> switch (ares->type) {
> case ACPI_RESOURCE_TYPE_MEMORY24:
> memory24 = &ares->data.memory24;
> - if (!memory24->address_length)
> + if (!memory24->minimum && !memory24->address_length)
> return false;
> acpi_dev_get_memresource(res, memory24->minimum,
> memory24->address_length,
> @@ -85,7 +85,7 @@ bool acpi_dev_resource_memory(struct acpi_resource *ares, struct resource *res)
> break;
> case ACPI_RESOURCE_TYPE_MEMORY32:
> memory32 = &ares->data.memory32;
> - if (!memory32->address_length)
> + if (!memory32->minimum && !memory32->address_length)
> return false;
> acpi_dev_get_memresource(res, memory32->minimum,
> memory32->address_length,
> @@ -93,7 +93,7 @@ bool acpi_dev_resource_memory(struct acpi_resource *ares, struct resource *res)
> break;
> case ACPI_RESOURCE_TYPE_FIXED_MEMORY32:
> fixed_memory32 = &ares->data.fixed_memory32;
> - if (!fixed_memory32->address_length)
> + if (!fixed_memory32->address && !fixed_memory32->address_length)
> return false;
> acpi_dev_get_memresource(res, fixed_memory32->address,
> fixed_memory32->address_length,
> @@ -150,7 +150,7 @@ bool acpi_dev_resource_io(struct acpi_resource *ares, struct resource *res)
> switch (ares->type) {
> case ACPI_RESOURCE_TYPE_IO:
> io = &ares->data.io;
> - if (!io->address_length)
> + if (!io->minimum && !io->address_length)
> return false;
> acpi_dev_get_ioresource(res, io->minimum,
> io->address_length,
> @@ -158,7 +158,7 @@ bool acpi_dev_resource_io(struct acpi_resource *ares, struct resource *res)
> break;
> case ACPI_RESOURCE_TYPE_FIXED_IO:
> fixed_io = &ares->data.fixed_io;
> - if (!fixed_io->address_length)
> + if (!fixed_io->address && !fixed_io->address_length)
> return false;
> acpi_dev_get_ioresource(res, fixed_io->address,
> fixed_io->address_length,
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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