From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <54BF0BA5.8020806@linux.intel.com> Date: Wed, 21 Jan 2015 10:15:01 +0800 From: Jiang Liu MIME-Version: 1.0 To: "Rafael J. Wysocki" CC: Thomas Gleixner , Bjorn Helgaas , Yinghai Lu , Borislav Petkov , Len Brown , Tony Luck , x86@kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org Subject: Re: [RFC Patch 09/19] ACPI: Fix a bug in parsing ACPI Memroy24 resource References: <1420684386-5975-1-git-send-email-jiang.liu@linux.intel.com> <1420684386-5975-10-git-send-email-jiang.liu@linux.intel.com> <1633329.njF7Ian1Kn@vostro.rjw.lan> In-Reply-To: <1633329.njF7Ian1Kn@vostro.rjw.lan> Content-Type: text/plain; charset=utf-8 Sender: linux-acpi-owner@vger.kernel.org List-ID: On 2015/1/21 8:42, Rafael J. Wysocki wrote: > On Thursday, January 08, 2015 10:32:56 AM Jiang Liu wrote: >> According to ACPI spec 5, section 6.4.3.1 "24-Bit Memory Range Descriptor", >> minimum, maximum and address_length field in struct acpi_resource_memory24 >> is in granularity of 256-bytes. So shift 8-bit left to get correct address. > > Are you sure about this? > > I'm reading ACPI 5.1 ATM and (on page 316) it only says about the range length > being in 256 byte blocks. Hi Rafael, According to ACPI spec 5.a sec 6.4.3.1, Byte 4, "Range minimum base address, _MIN, bits[7:0]", "Address bits[15:8] of the minimum base memory address for which the card may be configured." Byte 5, "Range minimum base address, _MIN, bits[15:8]", "Address bits[23:16] of the minimum base memory address for which the card may be configured". Byte 10, "Range length, _LEN, bits[7:0]", "This field contains the lower eight bits of the memory range length. The range length provides the length of the memory range in 256 byte blocks." Byte 11, "Range length, _LEN, bits[15:8]", "This field contains the upper eight bits of the memory range length. The range length field provides the length of the memory range in 256 byte blocks." That means _MIN defines bits[23:8] of the minimal address, and _LEN is in granularity of 256 bytes, so shift them left by 8 bits. Regards, Gerry > >> Signed-off-by: Jiang Liu >> --- >> drivers/acpi/resource.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c >> index abe3a29ad802..f4aeef22a9d8 100644 >> --- a/drivers/acpi/resource.c >> +++ b/drivers/acpi/resource.c >> @@ -90,8 +90,8 @@ bool acpi_dev_resource_memory(struct acpi_resource *ares, struct resource *res) >> switch (ares->type) { >> case ACPI_RESOURCE_TYPE_MEMORY24: >> memory24 = &ares->data.memory24; >> - acpi_dev_get_memresource(res, memory24->minimum, >> - memory24->address_length, >> + acpi_dev_get_memresource(res, memory24->minimum << 8, >> + memory24->address_length << 8, >> memory24->write_protect); >> break; >> case ACPI_RESOURCE_TYPE_MEMORY32: >> >