On Mon, Nov 03, 2014 at 08:58:34PM -0700, Azael Avalos wrote:
> Bug 86521 uncovered that some TOS6208 devices also return
> non zero values on a write call to the backlight method,
> thus getting caught and bailed out by the extra check code.
>
> This patch makes sure that the extra check is being done
> on a TOS1900 device and then make the check for the broken
> backlight code.
>
> Signed-off-by: Azael Avalos <coproscefalo@xxxxxxxxx>
> ---
> drivers/platform/x86/toshiba_acpi.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/x86/toshiba_acpi.c b/drivers/platform/x86/toshiba_acpi.c
> index ef3a190..e3fed12 100644
> --- a/drivers/platform/x86/toshiba_acpi.c
> +++ b/drivers/platform/x86/toshiba_acpi.c
> @@ -944,9 +944,13 @@ static int set_lcd_brightness(struct toshiba_acpi_dev *dev, int value)
> /* Extra check for "incomplete" backlight method, where the AML code
> * doesn't check for HCI_SET or HCI_GET and returns TOS_SUCCESS,
> * the actual brightness, and in some cases the max brightness.
> + * Use the SPFC method as an indicator that we're on a TOS1900 device,
> + * otherwise some TOS6208 devices might get bailed out, see bug 86521
This needs a clearer description here in this comment, rather than redirecting
the reader to a bug report (which may or may not exist when needed).
> */
> - if (out[2] > 0 || out[3] == 0xE000)
> - return -ENODEV;
> + if (acpi_has_method(dev->acpi_dev->handle, "SPFC")) {
Hrm, this checking for the existence of a specific method seems suspect to me.
We would know if we are on a TOS1900 as we matches the acpi id already. Is the
SPFC significant here, or is it just a "we only see SPFC on TOS1900 so it's a
convenient test"? If the latter, it seems rather fragile and prone to other
breakage to me.
Rafael, any recommendations here?
> + if (out[2] > 0 || out[3] == 0xE000)
> + return -ENODEV;
> + }
>
> return out[0] == TOS_SUCCESS ? 0 : -EIO;
> }
> --
> 2.1.1
>
>
--
Darren Hart
Intel Open Source Technology Center
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