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| author | Francisco Jerez <currojerez@riseup.net> | 2010-08-30 15:37:57 +0200 |
|---|---|---|
| committer | Ben Skeggs <bskeggs@redhat.com> | 2010-09-24 16:19:03 +1000 |
| commit | 7314dec95c054258d5e5a3d1d55e1fd042f8eaad (patch) | |
| tree | 3f4445cd0c96d186d15cff7182ad275e572cccdd /drivers/gpu/drm/nouveau/nv04_dac.c | |
| parent | 9d59e8a1fc8fc35bf22dc92d7722a7502769ab7e (diff) | |
| download | linux-7314dec95c054258d5e5a3d1d55e1fd042f8eaad.tar.bz2 | |
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>
Diffstat (limited to 'drivers/gpu/drm/nouveau/nv04_dac.c')
| -rw-r--r-- | drivers/gpu/drm/nouveau/nv04_dac.c | 2 |
1 files changed, 2 insertions, 0 deletions
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, |