Re: [PATCH] i915: slow acpi_lid_open() causes flickering

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 01 Feb 2010 19:20:53 +0100
Thomas Meyer <thomas@m3y3r.de> wrote:

> acpi_lid_open() could take up to 10ms on my computer.
> Some component is calling the drm GETCONNECTOR ioctl many times in a row.
> This results in flickering (for example, when starting a video).
> Fix it by assuming an always connected lid status.
> 
> This fixes bug http://bugzilla.kernel.org/show_bug.cgi?id=14670
> 
> ---
>  drivers/gpu/drm/i915/intel_lvds.c |   15 ++++++++++++++-
>  1 files changed, 14 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
> index aa74e59..0f0779c 100644
> --- a/drivers/gpu/drm/i915/intel_lvds.c
> +++ b/drivers/gpu/drm/i915/intel_lvds.c
> @@ -632,6 +632,18 @@ static const struct dmi_system_id bad_lid_status[] = {
>  	{ }
>  };
>  
> +/* Some lid devices take a long time to report the lid status, assume they're connected*/
> +static const struct dmi_system_id slow_lid_status[] = {
> +	{
> +		.ident = "Aspire 1810T",
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 1810T"),
> +		},
> +	},
> +	{ }
> +};
> +
>  /**
>   * Detect the LVDS connection.
>   *
> @@ -643,7 +655,8 @@ static enum drm_connector_status intel_lvds_detect(struct drm_connector *connect
>  {
>  	enum drm_connector_status status = connector_status_connected;
>  
> -	if (!acpi_lid_open() && !dmi_check_system(bad_lid_status))
> +	if (!dmi_check_system(slow_lid_status) && !dmi_check_system(bad_lid_status))
> +	    if (!acpi_lid_open())
>  		status = connector_status_disconnected;
>  
>  	return status;

The patch is missing your Signed-off-by: line.  I cheekily added it. 
Please check Documentation/SubmittingPatches, let me know if you
disagree with this, thanks.