The pre-retina MacBook Pro uses an LVDS panel and a gmux controller to switch the panel between its two GPUs. While the gmux is able to switch the DDC lines, we can also emulate DDC switching in software by using the active client as a proxy to talk to the panel. This gives us two ways to switch, one requiring the apple-gmux driver and the other requiring the active client's driver.
To that end, when probing DDC, if we're unable to talk to the panel ourselves and the connector in question is of type LVDS, try proxying via the vga_switcheroo active client.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=88861 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=61115 Tested-by: Paul Hordiienko pvt.gord@gmail.com [MBP 6,2 2010 intel ILK + nvidia GT216 pre-retina] Tested-by: William Brown william@blackhats.net.au [MBP 8,2 2011 intel SNB + amd turks pre-retina] Tested-by: Lukas Wunner lukas@wunner.de [MBP 9,1 2012 intel IVB + nvidia GK107 pre-retina] Tested-by: Bruno Bierbaumer bruno@bierbaumer.net [MBP 11,3 2013 intel HSW + nvidia GK107 retina -- work in progress]
Signed-off-by: Lukas Wunner lukas@wunner.de --- drivers/gpu/drm/nouveau/nouveau_connector.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c index 159df7f..d1a6982 100644 --- a/drivers/gpu/drm/nouveau/nouveau_connector.c +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c @@ -149,12 +149,18 @@ nouveau_connector_ddc_detect(struct drm_connector *connector) break; } else if (nv_encoder->i2c) { + struct i2c_adapter *proxy_ddc; int ret; vga_switcheroo_lock_ddc(dev->pdev); ret = nv_probe_i2c(nv_encoder->i2c, 0x50); vga_switcheroo_unlock_ddc(dev->pdev); if (ret) break; + proxy_ddc = vga_switcheroo_get_ddc(dev->pdev); + if (nv_encoder->dcb->type == DCB_OUTPUT_LVDS && + nv_connector->type == DCB_CONNECTOR_LVDS && + proxy_ddc && drm_probe_ddc(proxy_ddc)) + break; } }