From 7314dec95c054258d5e5a3d1d55e1fd042f8eaad Mon Sep 17 00:00:00 2001 From: Francisco Jerez <currojerez@riseup.net> Date: Mon, 30 Aug 2010 15:37:57 +0200 Subject: [PATCH] drm/nv17-nv4x: Fix analog load detection false positive on rare occasions. On some boards the residual current DAC outputs can draw when they're disconnected can be high enough to give a false load detection positive (I've only seen it in the S-video luma output of some cards, but just to be sure). The output line capacitance is limited and sampling twice should fix it reliably. Signed-off-by: Francisco Jerez <currojerez@riseup.net> Signed-off-by: Ben Skeggs <bskeggs@redhat.com> --- drivers/gpu/drm/nouveau/nv04_dac.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/nouveau/nv04_dac.c b/drivers/gpu/drm/nouveau/nv04_dac.c index ea3627041ecf..509c05015d50 100644 --- a/drivers/gpu/drm/nouveau/nv04_dac.c +++ b/drivers/gpu/drm/nouveau/nv04_dac.c @@ -291,6 +291,8 @@ uint32_t nv17_dac_sample_load(struct drm_encoder *encoder) msleep(5); sample = NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset); + /* do it again just in case it's a residual current */ + sample &= NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset); temp = NVReadRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL); NVWriteRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL, -- 2.30.9