msm: mdss: dp: set failsafe link params when DPCD read fails
For DPCD read failures, set link parameters corresponding to
the fail safe link resolution to conform to the display port
specification.
CRs-Fixed: 2010344
Change-Id: I06f56f508fe7adcb9e76f1a8597fc59cdadd741b
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>
diff --git a/drivers/video/fbdev/msm/mdss_dp.c b/drivers/video/fbdev/msm/mdss_dp.c
index 67adc46..619fab4 100644
--- a/drivers/video/fbdev/msm/mdss_dp.c
+++ b/drivers/video/fbdev/msm/mdss_dp.c
@@ -1793,8 +1793,6 @@
dp_drv->edid_buf = edid_init_data.buf;
dp_drv->edid_buf_size = edid_init_data.buf_size;
- mdss_dp_set_default_resolution(dp_drv);
-
return 0;
}
@@ -2009,14 +2007,21 @@
pr_debug("start\n");
- mdss_dp_dpcd_cap_read(dp);
+ ret = mdss_dp_dpcd_cap_read(dp);
+ if (ret || !mdss_dp_aux_is_link_rate_valid(dp->dpcd.max_link_rate) ||
+ !mdss_dp_aux_is_lane_count_valid(dp->dpcd.max_lane_count)) {
+ /*
+ * If there is an error in parsing DPCD or if DPCD reports
+ * unsupported link parameters then set the default link
+ * parameters and continue to read EDID.
+ */
+ pr_err("dpcd read failed, set failsafe parameters\n");
+ mdss_dp_set_default_link_parameters(dp);
+ }
ret = mdss_dp_edid_read(dp);
if (ret) {
- pr_debug("edid read error, setting default resolution\n");
-
- mdss_dp_set_default_resolution(dp);
- mdss_dp_set_default_link_parameters(dp);
+ pr_err("edid read error, setting default resolution\n");
goto notify;
}
@@ -2027,15 +2032,19 @@
ret = hdmi_edid_parser(dp->panel_data.panel_info.edid_data);
if (ret) {
pr_err("edid parse failed, setting default resolution\n");
-
- mdss_dp_set_default_resolution(dp);
- mdss_dp_set_default_link_parameters(dp);
goto notify;
}
dp->sink_info_read = true;
notify:
+ if (ret) {
+ /* set failsafe parameters */
+ pr_info("falling back to failsafe mode\n");
+ mdss_dp_set_default_resolution(dp);
+ mdss_dp_set_default_link_parameters(dp);
+ }
+
/* Check if there is a PHY_TEST_PATTERN request when we get HPD high.
* Update the DP driver with the test parameters including link rate,
* lane count, voltage level, and pre-emphasis level. Do not notify
diff --git a/drivers/video/fbdev/msm/mdss_dp.h b/drivers/video/fbdev/msm/mdss_dp.h
index 34b652d..4decb26ea 100644
--- a/drivers/video/fbdev/msm/mdss_dp.h
+++ b/drivers/video/fbdev/msm/mdss_dp.h
@@ -1038,7 +1038,7 @@
void mdss_dp_phy_initialize(struct mdss_dp_drv_pdata *dp);
-void mdss_dp_dpcd_cap_read(struct mdss_dp_drv_pdata *dp);
+int mdss_dp_dpcd_cap_read(struct mdss_dp_drv_pdata *dp);
int mdss_dp_dpcd_status_read(struct mdss_dp_drv_pdata *dp);
void mdss_dp_aux_parse_sink_status_field(struct mdss_dp_drv_pdata *dp);
int mdss_dp_edid_read(struct mdss_dp_drv_pdata *dp);
diff --git a/drivers/video/fbdev/msm/mdss_dp_aux.c b/drivers/video/fbdev/msm/mdss_dp_aux.c
index 479c367..8566b1d 100644
--- a/drivers/video/fbdev/msm/mdss_dp_aux.c
+++ b/drivers/video/fbdev/msm/mdss_dp_aux.c
@@ -826,9 +826,9 @@
return ret;
}
-static void dp_sink_capability_read(struct mdss_dp_drv_pdata *ep,
- int len)
+int mdss_dp_dpcd_cap_read(struct mdss_dp_drv_pdata *ep)
{
+ int const len = 16; /* read 16 bytes */
char *bp;
char data;
struct dpcd_cap *cap;
@@ -838,8 +838,15 @@
rlen = dp_aux_read_buf(ep, 0, len, 0);
if (rlen <= 0) {
pr_err("edp aux read failed\n");
- return;
+ return rlen;
}
+
+ if (rlen != len) {
+ pr_debug("Read size expected(%d) bytes, actual(%d) bytes\n",
+ len, rlen);
+ return -EINVAL;
+ }
+
rp = &ep->rxp;
cap = &ep->dpcd;
bp = rp->data;
@@ -849,15 +856,11 @@
data = *bp++; /* byte 0 */
cap->major = (data >> 4) & 0x0f;
cap->minor = data & 0x0f;
- if (--rlen <= 0)
- return;
pr_debug("version: %d.%d\n", cap->major, cap->minor);
data = *bp++; /* byte 1 */
/* 162, 270 and 540 MB, symbol rate, NOT bit rate */
cap->max_link_rate = data;
- if (--rlen <= 0)
- return;
pr_debug("link_rate=%d\n", cap->max_link_rate);
data = *bp++; /* byte 2 */
@@ -873,8 +876,6 @@
data &= 0x0f;
cap->max_lane_count = data;
- if (--rlen <= 0)
- return;
pr_debug("lane_count=%d\n", cap->max_lane_count);
data = *bp++; /* byte 3 */
@@ -887,14 +888,10 @@
cap->flags |= DPCD_NO_AUX_HANDSHAKE;
pr_debug("NO Link Training\n");
}
- if (--rlen <= 0)
- return;
data = *bp++; /* byte 4 */
cap->num_rx_port = (data & BIT(0)) + 1;
pr_debug("rx_ports=%d", cap->num_rx_port);
- if (--rlen <= 0)
- return;
data = *bp++; /* Byte 5: DOWN_STREAM_PORT_PRESENT */
cap->downstream_port.dfp_present = data & BIT(0);
@@ -907,13 +904,8 @@
pr_debug("format_conversion = %d, detailed_cap_info_available = %d\n",
cap->downstream_port.format_conversion,
cap->downstream_port.detailed_cap_info_available);
- if (--rlen <= 0)
- return;
bp += 1; /* Skip Byte 6 */
- rlen -= 1;
- if (rlen <= 0)
- return;
data = *bp++; /* Byte 7: DOWN_STREAM_PORT_COUNT */
cap->downstream_port.dfp_count = data & 0x7;
@@ -923,34 +915,23 @@
cap->downstream_port.dfp_count,
cap->downstream_port.msa_timing_par_ignored);
pr_debug("oui_support = %d\n", cap->downstream_port.oui_support);
- if (--rlen <= 0)
- return;
data = *bp++; /* byte 8 */
if (data & BIT(1)) {
cap->flags |= DPCD_PORT_0_EDID_PRESENTED;
pr_debug("edid presented\n");
}
- if (--rlen <= 0)
- return;
data = *bp++; /* byte 9 */
cap->rx_port0_buf_size = (data + 1) * 32;
pr_debug("lane_buf_size=%d\n", cap->rx_port0_buf_size);
- if (--rlen <= 0)
- return;
bp += 2; /* skip 10, 11 port1 capability */
- rlen -= 2;
- if (rlen <= 0)
- return;
data = *bp++; /* byte 12 */
cap->i2c_speed_ctrl = data;
if (cap->i2c_speed_ctrl > 0)
pr_debug("i2c_rate=%d", cap->i2c_speed_ctrl);
- if (--rlen <= 0)
- return;
data = *bp++; /* byte 13 */
cap->scrambler_reset = data & BIT(0);
@@ -962,8 +943,6 @@
pr_debug("enhanced_framing=%d\n",
cap->enhanced_frame);
- if (--rlen <= 0)
- return;
data = *bp++; /* byte 14 */
if (data == 0)
@@ -974,6 +953,8 @@
cap->training_read_interval);
dp_sink_parse_sink_count(ep);
+
+ return 0;
}
int mdss_dp_aux_link_status_read(struct mdss_dp_drv_pdata *ep, int len)
@@ -2379,11 +2360,6 @@
return ret;
}
-void mdss_dp_dpcd_cap_read(struct mdss_dp_drv_pdata *ep)
-{
- dp_sink_capability_read(ep, 16);
-}
-
void mdss_dp_aux_parse_sink_status_field(struct mdss_dp_drv_pdata *ep)
{
dp_sink_parse_sink_count(ep);
