Bring sink out of D3 (power down) mode into D0 (normal operation) mode
by setting DP_SET_POWER_D0 bit to DP_SET_POWER dpcd register. This
patch will retry 3 times if written to DP_SET_POWER register failed.
Changes in v4:
-- split into two patches
Signed-off-by: Kuogee Hsieh <quic_khs...@quicinc.com>
---
drivers/gpu/drm/msm/dp/dp_link.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/msm/dp/dp_link.c b/drivers/gpu/drm/msm/dp/dp_link.c
index 36f0af0..7b5ecf5 100644
--- a/drivers/gpu/drm/msm/dp/dp_link.c
+++ b/drivers/gpu/drm/msm/dp/dp_link.c
@@ -49,23 +49,26 @@ static int dp_aux_link_power_up(struct drm_dp_aux *aux,
struct dp_link_info *link)
{
u8 value;
- int err;
+ ssize_t len;
+ int i;
if (link->revision < 0x11)
return 0;
- err = drm_dp_dpcd_readb(aux, DP_SET_POWER, &value);
- if (err < 0)
- return err;
+ len = drm_dp_dpcd_readb(aux, DP_SET_POWER, &value);
+ if (len < 0)
+ return len;
value &= ~DP_SET_POWER_MASK;
value |= DP_SET_POWER_D0;
- err = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value);
- if (err < 0)
- return err;
-
- usleep_range(1000, 2000);
+ /* retry for 1ms to give the sink time to wake up */
+ for (i = 0; i < 3; i++) {
+ len = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value);
+ usleep_range(1000, 2000);
+ if (len == 1)
+ break;
+ }
return 0;
}
--
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