diff options
| author | Jonathan Gray <jsg@cvs.openbsd.org> | 2014-02-02 01:06:22 +0000 |
|---|---|---|
| committer | Jonathan Gray <jsg@cvs.openbsd.org> | 2014-02-02 01:06:22 +0000 |
| commit | fe55dfde82d2faf80a3ca92ba365c26ec5e2ad02 (patch) | |
| tree | 43132f50575007bd0b588eff23b86ba9c4093a97 | |
| parent | 45768120191e1b8b78f90445c24a3212fa146b04 (diff) | |
drm/i915/dp: increase i2c-over-aux retry interval on AUX DEFER
From Jani Nikula
67c729e64ef03476312fc9fb815046d5e540428a in ubuntu 3.8
8d16f258217f2f583af1fd57c5144aa4bbe73e48 in mainline linux
| -rw-r--r-- | sys/dev/pci/drm/i915/intel_dp.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/sys/dev/pci/drm/i915/intel_dp.c b/sys/dev/pci/drm/i915/intel_dp.c index db19006bb37..29dc199eb14 100644 --- a/sys/dev/pci/drm/i915/intel_dp.c +++ b/sys/dev/pci/drm/i915/intel_dp.c @@ -1,4 +1,4 @@ -/* $OpenBSD: intel_dp.c,v 1.14 2014/01/23 10:42:57 jsg Exp $ */ +/* $OpenBSD: intel_dp.c,v 1.15 2014/02/02 01:06:21 jsg Exp $ */ /* * Copyright © 2008 Intel Corporation * @@ -629,7 +629,18 @@ intel_dp_i2c_aux_ch(struct i2c_controller *adapter, int mode, DRM_DEBUG_KMS("aux_ch native nack\n"); return -EIO; case AUX_NATIVE_REPLY_DEFER: - udelay(100); + /* + * For now, just give more slack to branch devices. We + * could check the DPCD for I2C bit rate capabilities, + * and if available, adjust the interval. We could also + * be more careful with DP-to-Legacy adapters where a + * long legacy cable may force very low I2C bit rates. + */ + if (intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & + DP_DWN_STRM_PORT_PRESENT) + usleep_range(500, 600); + else + usleep_range(300, 400); continue; default: DRM_ERROR("aux_ch invalid native reply 0x%02x\n", |