diff options
author | David S. Miller <davem@davemloft.net> | 2018-04-24 23:59:11 -0400 |
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committer | David S. Miller <davem@davemloft.net> | 2018-04-24 23:59:11 -0400 |
commit | c749fa181bd5848be78691d23168ec61ce691b95 (patch) | |
tree | d037dc016bd880d9d5b393a30f3907ef5e98124d /drivers/gpu/drm/drm_dp_dual_mode_helper.c | |
parent | 16f4faa4f06ff3b4e214922d55ac33ab6e2bdbdc (diff) | |
parent | 3be4aaf4e2d3eb95cce7835e8df797ae65ae5ac1 (diff) | |
download | op-kernel-dev-c749fa181bd5848be78691d23168ec61ce691b95.zip op-kernel-dev-c749fa181bd5848be78691d23168ec61ce691b95.tar.gz |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Diffstat (limited to 'drivers/gpu/drm/drm_dp_dual_mode_helper.c')
-rw-r--r-- | drivers/gpu/drm/drm_dp_dual_mode_helper.c | 39 |
1 files changed, 32 insertions, 7 deletions
diff --git a/drivers/gpu/drm/drm_dp_dual_mode_helper.c b/drivers/gpu/drm/drm_dp_dual_mode_helper.c index 02a5092..e7f4fe2 100644 --- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c @@ -350,19 +350,44 @@ int drm_dp_dual_mode_set_tmds_output(enum drm_dp_dual_mode_type type, { uint8_t tmds_oen = enable ? 0 : DP_DUAL_MODE_TMDS_DISABLE; ssize_t ret; + int retry; if (type < DRM_DP_DUAL_MODE_TYPE2_DVI) return 0; - ret = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_TMDS_OEN, - &tmds_oen, sizeof(tmds_oen)); - if (ret) { - DRM_DEBUG_KMS("Failed to %s TMDS output buffers\n", - enable ? "enable" : "disable"); - return ret; + /* + * LSPCON adapters in low-power state may ignore the first write, so + * read back and verify the written value a few times. + */ + for (retry = 0; retry < 3; retry++) { + uint8_t tmp; + + ret = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_TMDS_OEN, + &tmds_oen, sizeof(tmds_oen)); + if (ret) { + DRM_DEBUG_KMS("Failed to %s TMDS output buffers (%d attempts)\n", + enable ? "enable" : "disable", + retry + 1); + return ret; + } + + ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_TMDS_OEN, + &tmp, sizeof(tmp)); + if (ret) { + DRM_DEBUG_KMS("I2C read failed during TMDS output buffer %s (%d attempts)\n", + enable ? "enabling" : "disabling", + retry + 1); + return ret; + } + + if (tmp == tmds_oen) + return 0; } - return 0; + DRM_DEBUG_KMS("I2C write value mismatch during TMDS output buffer %s\n", + enable ? "enabling" : "disabling"); + + return -EIO; } EXPORT_SYMBOL(drm_dp_dual_mode_set_tmds_output); |