Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751896AbaAXRFp (ORCPT ); Fri, 24 Jan 2014 12:05:45 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:54322 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751115AbaAXRFn (ORCPT ); Fri, 24 Jan 2014 12:05:43 -0500 From: "Rafael J. Wysocki" To: Bjorn Helgaas Cc: Yijing Wang , "Rafael J. Wysocki" , "linux-acpi@vger.kernel.org" , Daniel Vetter , Jani Nikula , Konrad Rzeszutek Wilk , David Airlie , intel-gfx@lists.freedesktop.org, DRI mailing list , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , Dave Airlie , Hanjun Guo Subject: Re: [PATCH v5] ACPI: Fix acpi_evaluate_object() return value check Date: Fri, 24 Jan 2014 18:19:55 +0100 Message-ID: <4891976.lTa9ZQzyVA@vostro.rjw.lan> User-Agent: KMail/4.11.4 (Linux/3.13.0-rc8+; KDE/4.11.4; x86_64; ; ) In-Reply-To: References: <1390448559-33896-1-git-send-email-wangyijing@huawei.com> <11909895.7rJ1jejxPI@vostro.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, January 24, 2014 08:25:23 AM Bjorn Helgaas wrote: > On Fri, Jan 24, 2014 at 8:36 AM, Rafael J. Wysocki wrote: > > On Friday, January 24, 2014 07:54:29 AM Bjorn Helgaas wrote: > >> On Thu, Jan 23, 2014 at 5:33 PM, Rafael J. Wysocki wrote: > >> > On Thursday, January 23, 2014 11:21:01 AM Bjorn Helgaas wrote: > >> >> On Wed, Jan 22, 2014 at 8:42 PM, Yijing Wang wrote: > >> >> > Since acpi_evaluate_object() returns acpi_status and not plain int, > >> >> > ACPI_FAILURE() should be used for checking its return value. Also > >> >> > add some detailed debug info when acpi_evaluate_object() failed. > >> >> > > >> >> > Reviewed-by: Jani Nikula > >> >> > Acked-by: Bjorn Helgaas > >> >> > Signed-off-by: Yijing Wang > >> >> > --- > >> >> > v4->v5: Add some detailed debug info for acpi_evaluate_object() > >> >> > failure suggested by Bjorn. > >> >> > v3->v4: Fix spell error, add Jani Nikula reviewed-by. > >> >> > v2->v3: Fix compile error pointed out by Hanjun. > >> >> > v1->v2: Add CC to related subsystem MAINTAINERS > >> >> > --- > >> >> > drivers/gpu/drm/i915/intel_acpi.c | 33 ++++++++++++++++------- > >> >> > drivers/gpu/drm/nouveau/core/subdev/mxm/base.c | 13 ++++++--- > >> >> > drivers/gpu/drm/nouveau/nouveau_acpi.c | 25 +++++++++++------- > >> >> > drivers/pci/pci-label.c | 10 +++++-- > >> >> > 4 files changed, 54 insertions(+), 27 deletions(-) > >> >> > > >> >> > diff --git a/drivers/gpu/drm/i915/intel_acpi.c b/drivers/gpu/drm/i915/intel_acpi.c > >> >> > index dfff090..e7b526b 100644 > >> >> > --- a/drivers/gpu/drm/i915/intel_acpi.c > >> >> > +++ b/drivers/gpu/drm/i915/intel_acpi.c > >> >> > @@ -31,11 +31,13 @@ static const u8 intel_dsm_guid[] = { > >> >> > static int intel_dsm(acpi_handle handle, int func) > >> >> > { > >> >> > struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; > >> >> > + struct acpi_buffer string = { ACPI_ALLOCATE_BUFFER, NULL }; > >> >> > struct acpi_object_list input; > >> >> > union acpi_object params[4]; > >> >> > union acpi_object *obj; > >> >> > u32 result; > >> >> > - int ret = 0; > >> >> > + acpi_status status; > >> >> > + int ret; > >> >> > > >> >> > input.count = 4; > >> >> > input.pointer = params; > >> >> > @@ -50,10 +52,14 @@ static int intel_dsm(acpi_handle handle, int func) > >> >> > params[3].package.count = 0; > >> >> > params[3].package.elements = NULL; > >> >> > > >> >> > - ret = acpi_evaluate_object(handle, "_DSM", &input, &output); > >> >> > - if (ret) { > >> >> > - DRM_DEBUG_DRIVER("failed to evaluate _DSM: %d\n", ret); > >> >> > - return ret; > >> >> > + status = acpi_evaluate_object(handle, "_DSM", &input, &output); > >> >> > + if (ACPI_FAILURE(status)) { > >> >> > + acpi_get_name(handle, ACPI_FULL_PATHNAME, &string); > >> >> > + DRM_DEBUG_DRIVER( > >> >> > + "failed to evaluate _DSM for %s, exit status %u\n", > >> >> > + (char *)string.pointer, (unsigned int)status); > >> >> > + kfree(string.pointer); > >> >> > + return -EINVAL; > >> >> > >> >> I said "too bad there isn't an *easy* way" to include more > >> >> information. IMHO this is too ugly and error-prone to use > >> >> consistently. And if you are going to add more information, why did > >> >> you only do it for some of the calls and not others? > >> >> > >> >> I considered adding a %p extension to print the pathname; I don't know > >> >> if that's worthwhile or not. I think it would be ideal if we had a > >> >> struct device and could use dev_info(), and then a way to connect the > >> >> struct device with an ACPI path, like maybe a dmesg note when we > >> >> create the struct device corresponding to an ACPI Device node. > >> > > >> > Well, we can generally print something like that from pci_acpi_setup(). > >> > > >> > What about the below? Wouldn't it generate too much output on some systems? > >> > >> Yeah, that probably would generate an awful lot of output. I was just > >> hoping to avoid treating ACPI pathnames as first-class objects. What > >> do you think about a %p extension? I played with that once, but I > >> seem to have lost the patch. > > > > Well, it may be worth doing. However, that information is readily available from > > sysfs anyway, you only need to follow the firmware_node link in the PCI device's > > sysfs directory and read the path attribute from there. For example, on my > > system: > > > > $ cat /sys/devices/pci0000:00/0000:00:1c.4/0000:0b:00.0/firmware_node/path > > \_SB_.PCI0.RP05.PXSX > > That's perfect. If we had a struct device, we could just use > dev_info() for these messages. But I have no idea how hard it would > be to get at the struct device. >From the pci_dev side that is trivial: use ACPI_COMPANION(). The other way around is rather more difficult as browsing a list would be involved. Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/