[PATCH v2.1 2/3] apple-gmux: Add switch_ddc support
Daniel Vetter
daniel at ffwll.ch
Tue Aug 25 01:13:58 PDT 2015
On Fri, Aug 14, 2015 at 06:18:55PM +0200, Lukas Wunner wrote:
> Originally by Seth Forshee <seth.forshee at canonical.com>, 2012-10-04:
> The gmux allows muxing the DDC independently from the display, so
> support this functionality. This will allow reading the EDID for the
> inactive GPU, fixing issues with machines that either don't have a VBT
> or have invalid mode data in the VBT.
>
> Modified by Lukas Wunner <lukas at wunner.de>, 2015-03-27:
> If the inactive client registers before the active client then
> old_ddc_owner cannot be determined with find_active_client()
> (null pointer dereference). Therefore change semantics of the
> ->switch_ddc handler callback to return old_ddc_owner.
>
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=88861
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61115
> Tested-by: Pierre Moreau <pierre.morrow at free.fr>
> [MBP 5,3 2009 nvidia 9400M + 9600M GT pre-retina]
> Tested-by: Paul Hordiienko <pvt.gord at gmail.com>
> [MBP 6,2 2010 intel ILK + nvidia GT216 pre-retina]
> Tested-by: William Brown <william at blackhats.net.au>
> [MBP 8,2 2011 intel SNB + amd turks pre-retina]
> Tested-by: Lukas Wunner <lukas at wunner.de>
> [MBP 9,1 2012 intel IVB + nvidia GK107 pre-retina]
> Tested-by: Bruno Bierbaumer <bruno at bierbaumer.net>
> [MBP 11,3 2013 intel HSW + nvidia GK107 retina -- work in progress]
>
> Cc: Seth Forshee <seth.forshee at canonical.com>
> Signed-off-by: Lukas Wunner <lukas at wunner.de>
> ---
> drivers/platform/x86/apple-gmux.c | 25 +++++++++++++++++++++++--
> 1 file changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
> index 0dec3f5..08bdf1e 100644
> --- a/drivers/platform/x86/apple-gmux.c
> +++ b/drivers/platform/x86/apple-gmux.c
> @@ -273,14 +273,34 @@ static const struct backlight_ops gmux_bl_ops = {
> .update_status = gmux_update_status,
> };
>
> +static int gmux_switch_ddc(enum vga_switcheroo_client_id id)
> +{
> + enum vga_switcheroo_client_id old_ddc_owner;
> +
> + if (gmux_read8(apple_gmux_data, GMUX_PORT_SWITCH_DDC) == 1)
> + old_ddc_owner = VGA_SWITCHEROO_IGD;
> + else
> + old_ddc_owner = VGA_SWITCHEROO_DIS;
> +
> + pr_debug("Switching gmux DDC from %d to %d\n", old_ddc_owner, id);
> +
> + if (id == old_ddc_owner)
> + return old_ddc_owner;
> +
> + if (id == VGA_SWITCHEROO_IGD)
> + gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1);
> + else
> + gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2);
> +
> + return old_ddc_owner;
> +}
> +
> static int gmux_switchto(enum vga_switcheroo_client_id id)
> {
> if (id == VGA_SWITCHEROO_IGD) {
> - gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 1);
> gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DISPLAY, 2);
> gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 2);
> } else {
> - gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DDC, 2);
> gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_DISPLAY, 3);
> gmux_write8(apple_gmux_data, GMUX_PORT_SWITCH_EXTERNAL, 3);
> }
> @@ -347,6 +367,7 @@ gmux_active_client(struct apple_gmux_data *gmux_data)
> }
If we'd required that switchto also switches ddc then the error handling
in patch 1 would be a lot simpler. switch_ddc would then only be for
temporary switching while probing.
-Daniel
>
> static struct vga_switcheroo_handler gmux_handler = {
> + .switch_ddc = gmux_switch_ddc,
> .switchto = gmux_switchto,
> .power_state = gmux_set_power_state,
> .get_client_id = gmux_get_client_id,
> --
> 2.1.0
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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