Re: [PATCH v5] ACPI: Fix acpi_evaluate_object() return value check

From: Rafael J. Wysocki
Date: Thu Jan 23 2014 - 19:19:18 EST


On Thursday, January 23, 2014 11:21:01 AM Bjorn Helgaas wrote:
> On Wed, Jan 22, 2014 at 8:42 PM, Yijing Wang <wangyijing@xxxxxxxxxx> 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 <jani.nikula@xxxxxxxxx>
> > Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
> > ---
> > 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?

Rafael


---
drivers/pci/pci-acpi.c | 2 ++
1 file changed, 2 insertions(+)

Index: linux-pm/drivers/pci/pci-acpi.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-acpi.c
+++ linux-pm/drivers/pci/pci-acpi.c
@@ -330,6 +330,8 @@ static void pci_acpi_setup(struct device
if (!adev)
return;

+ acpi_handle_info(adev->handle, "bound to %s\n", dev_name(dev));
+
pci_acpi_add_pm_notifier(adev, pci_dev);
if (!adev->wakeup.flags.valid)
return;

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