On Fri, Aug 14, 2015 at 12:18 PM, Lukas Wunner <lukas at wunner.de> 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>, 2015-10-07:
> Advertise ->switch_ddc handler callback only on the pre-retina
> Macbook Pro. The retina uses eDP and its mux is incapable of
> switching the AUX channel separately from the main link.
> It's an NXP CBTL06142 (alternate parts: TI HD3SS212,
> Pericom PPI3VDP12412).
>
> Sources:
> http://www.electronicproducts.com/-whatsinside_text-145.aspx
>
> http://slideshare.net/jjwu6266/apple-2012-wwdc-apple-macbook-pro-with-retina-display
>
> http://www.techrepublic.com/blog/cracking-open/teardown-shows-retina-macbook-pro-is-nearly-impossible-to-upgrade-difficult-to-work-on/
>
> Datasheets:
> http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
> http://www.ti.com/lit/ds/symlink/hd3ss212.pdf
> https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf
>
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=88861
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61115
> Tested-by: Lukas Wunner <lukas at wunner.de>
> [MBP 9,1 2012 intel IVB + nvidia GK107 pre-retina 15"]
>
> Cc: Seth Forshee <seth.forshee at canonical.com>
> Signed-off-by: Lukas Wunner <lukas at wunner.de>
> ---
> drivers/platform/x86/apple-gmux.c | 21 +++++++++++++++++++--
> 1 file changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/x86/apple-gmux.c
> b/drivers/platform/x86/apple-gmux.c
> index 0dec3f5..78997b7 100644
> --- a/drivers/platform/x86/apple-gmux.c
> +++ b/drivers/platform/x86/apple-gmux.c
> @@ -276,11 +276,9 @@ static const struct backlight_ops gmux_bl_ops = {
> 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);
> }
Won't this hunk break manual switching until the later patches land?
Seems like you might want to break this out as a separate patch later
in the series.
Alex
> @@ -288,6 +286,18 @@ static int gmux_switchto(enum vga_switcheroo_client_id
> id)
> return 0;
> }
>
> +static int gmux_switch_ddc(enum vga_switcheroo_client_id id)
> +{
> + pr_debug("Switching gmux DDC to %d\n", id);
> +
> + 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 0;
> +}
> +
> static int gmux_set_discrete_state(struct apple_gmux_data *gmux_data,
> enum vga_switcheroo_state state)
> {
> @@ -588,6 +598,13 @@ static int gmux_probe(struct pnp_dev *pnp, const struct
> pnp_device_id *id)
> gmux_data->gpe = -1;
> }
>
> + /*
> + * The gmux in pre-retina MacBook Pros can switch DDC separately
> + * from the other pins of the outputs. It's distinguishable from
> + * the gmux in retinas by being non-indexed.
> + */
> + if (!gmux_data->indexed)
> + gmux_handler.switch_ddc = gmux_switch_ddc;
> if (vga_switcheroo_register_handler(&gmux_handler)) {
> ret = -ENODEV;
> goto err_register_handler;
> --
> 1.8.5.2 (Apple Git-48)
>
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