Hi Greg,
Thank you for your comments, some answers below.
On 13/4/20 16:12, Greg Kroah-Hartman wrote:
> Meta-comment to the ACPI developers, shouldn't all of this happen
> "automatically" with the existing ACPI entries in sysfs? If not, is
> this driver the proper way to do this?
>
This is something maintainers didn't answer yet, and I am not sure, to be hones,
but meanwhile, I'll rework this driver fixing the Greg comments and send a new
version.
> Minor review comments below:
>
>
> On Mon, Apr 13, 2020 at 03:46:11PM +0200, Enric Balletbo i Serra wrote:
>> +What: /sys/bus/acpi/devices/GGL0001:00/BINF.{0,1,4}
>> +Date: April 2020
>> +KernelVersion: 5.8
>> +Description:
>> + This file is reserved and doesn't shows useful information
>> + for now.
>
> Then do not even have it present. sysfs should never export files that
> nothing can be done with them, userspace "knows" that if a file is not
> present, it can not use it. Bring it back when it is useful.
>
Makes sense. I'll do in next version.
>> +What: /sys/bus/acpi/devices/GGL0001:00/MECK
>> +Date: April 2020
>> +KernelVersion: 5.8
>> +Description:
>> + This binary file returns the SHA-1 or SHA-256 hash that is
>> + read out of the Management Engine extend registers during
>> + boot. The hash is exported vi ACPI so the OS can verify that
>> + the Management Engine firmware has not changed. If Management
>> + Engine is not present, or if the firmware was unable to read the
>> + extend registers, this buffer can be zero.
>
> The size is zero, or the contents are 0?
>
The size. I'll reword in the description,
>> +static char *chromeos_acpi_alloc_name(char *name, int count, int index)
>> +{
>> + char *str;
>> +
>> + if (count == 1)
>> + str = kstrdup(name, GFP_KERNEL);
>> + else
>> + str = kasprintf(GFP_KERNEL, "%s.%d", name, index);
>
> That's crazy, make this more obvious that "count" affects the name so
> much. As it is, no one would know this unless they read the function
> code, and not just the name.
>
I see, let me think about this.
>
>> +/**
>> + * chromeos_acpi_add_group() - Create a sysfs group including attributes
>> + * representing a nested ACPI package.
>> + *
>> + * @adev: ACPI device.
>> + * @obj: Package contents as returned by ACPI.
>> + * @name: Name of the group.
>> + * @num_attrs: Number of attributes of this package.
>> + * @index: Index number of this particular group.
>> + *
>> + * The created group is called @name in case there is a single instance, or
>> + * @name.@index otherwise.
>> + *
>> + * All group and attribute storage allocations are included in the lists for
>> + * tracking of allocated memory.
>> + *
>> + * Return: 0 on success, negative errno on failure.
>> + */
>
> Meta-comment, no need for kerneldoc on static functions. It's nice to
> see, but nothing is going to notice them...
>
>> +static int chromeos_acpi_add_method(struct acpi_device *adev, char *name)
>> +{
>> + struct device *dev = &adev->dev;
>> + struct acpi_buffer output;
>> + union acpi_object *obj;
>> + acpi_status status;
>> + int ret = 0;
>> +
>> + output.length = ACPI_ALLOCATE_BUFFER;
>> +
>> + status = acpi_evaluate_object(adev->handle, name, NULL, &output);
>> + if (ACPI_FAILURE(status)) {
>> + dev_err(dev, "failed to retrieve %s (%d)\n", name, status);
>> + return status;
>> + }
>> +
>> + obj = output.pointer;
>> + if (obj->type == ACPI_TYPE_PACKAGE)
>> + ret = chromeos_acpi_handle_package(adev, obj, name);
>> +
>> + kfree(output.pointer);
>
> Why the need for 'obj' at all in this function? Minor nit.
>
Ok, I'll remove obj.
>> +
>> + return ret;
>> +}
>> +
>> +static int chromeos_acpi_device_add(struct acpi_device *adev)
>> +{
>> + struct chromeos_acpi_attribute_group *aag = chromeos_acpi.root;
>> + struct device *dev = &adev->dev;
>> + int i, ret;
>> +
>> + aag = kzalloc(sizeof(*aag), GFP_KERNEL);
>> + if (!aag)
>> + return -ENOMEM;
>> +
>> + INIT_LIST_HEAD(&aag->attribs);
>> + INIT_LIST_HEAD(&aag->list);
>> + INIT_LIST_HEAD(&chromeos_acpi.groups);
>> +
>> + chromeos_acpi.root = aag;
>> +
>> + /*
>> + * Attempt to add methods by querying the device's MLST method
>> + * for the list of methods.
>> + */
>> + if (!chromeos_acpi_process_mlst(adev))
>> + return 0;
>> +
>> + dev_info(dev, "falling back to default list of methods\n");
>
> Is this debugging code left over? If not, make it an error, and what
> would a user be able to do with it?
>
I think I can downgrade to debug level.
Thanks,
Enric
> thanks,
>
> greg k-h
>
