Add a new drm_debug bit for turning on DPCD logging, to aid debugging
with troublesome monitors.
v2: don't try to hexdump the universe if driver returns -errno, and
change the "too many retries" traces to DRM_ERROR()
Signed-off-by: Rob Clark <robdclark@xxxxxxxxx>
---
drivers/gpu/drm/drm_dp_helper.c | 60 ++++++++++++++++++++++++++++++++++-------
include/drm/drmP.h | 10 ++++++-
2 files changed, 59 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 76e08dc..3f27cc9 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -159,6 +159,44 @@ int drm_dp_bw_code_to_link_rate(u8 link_bw)
}
EXPORT_SYMBOL(drm_dp_bw_code_to_link_rate);
+static ssize_t aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
+{
+ ssize_t ret;
+
+ DRM_DEBUG_DPCD("%s: req=0x%02x, address=0x%05x, size=%zu\n", aux->name,
+ msg->request, msg->address, msg->size);
+
+ if (unlikely(drm_debug & DRM_UT_DPCD)) {
+ switch (msg->request & ~DP_AUX_I2C_MOT) {
+ case DP_AUX_NATIVE_WRITE:
+ case DP_AUX_I2C_WRITE:
+ print_hex_dump(KERN_DEBUG, "DPCD: ", DUMP_PREFIX_OFFSET,
+ 16, 1, msg->buffer, msg->size, false);
+ break;
+ default:
+ break;
+ }
+ }
+
+ ret = aux->transfer(aux, msg);
+
+ DRM_DEBUG_DPCD("%s: reply=0x%02x, size=%zd\n", aux->name, msg->reply, ret);
+
+ if (unlikely(drm_debug & DRM_UT_DPCD) && (ret > 0)) {
+ switch (msg->request & ~DP_AUX_I2C_MOT) {
+ case DP_AUX_NATIVE_READ:
+ case DP_AUX_I2C_READ:
+ print_hex_dump(KERN_DEBUG, "DPCD: ", DUMP_PREFIX_OFFSET,
+ 16, 1, msg->buffer, ret, false);
+ break;
+ default:
+ break;
+ }
+ }
+
+ return ret;
+}
+
#define AUX_RETRY_INTERVAL 500 /* us */
/**
@@ -196,7 +234,7 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request,
*/
for (retry = 0; retry < 32; retry++) {
- err = aux->transfer(aux, &msg);
+ err = aux_transfer(aux, &msg);
if (err < 0) {
if (err == -EBUSY)
continue;
@@ -212,16 +250,18 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request,
goto unlock;
case DP_AUX_NATIVE_REPLY_NACK:
+ DRM_DEBUG_DPCD("native nack (result=%d, size=%zu)\n", err, msg.size);
err = -EIO;
goto unlock;
case DP_AUX_NATIVE_REPLY_DEFER:
+ DRM_DEBUG_DPCD("native defer\n");
usleep_range(AUX_RETRY_INTERVAL, AUX_RETRY_INTERVAL + 100);
break;
}
}
- DRM_DEBUG_KMS("too many retries, giving up\n");
+ DRM_ERROR("DPCD: too many retries, giving up!\n");
err = -EIO;
unlock:
@@ -550,12 +590,12 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
WARN_ON(!mutex_is_locked(&aux->hw_mutex));
for (retry = 0, defer_i2c = 0; retry < (max_retries + defer_i2c); retry++) {
- ret = aux->transfer(aux, msg);
+ ret = aux_transfer(aux, msg);
if (ret < 0) {
if (ret == -EBUSY)
continue;
- DRM_DEBUG_KMS("transaction failed: %d\n", ret);
+ DRM_DEBUG_DPCD("transaction failed: %d\n", ret);
return ret;
}
@@ -569,11 +609,11 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
break;
case DP_AUX_NATIVE_REPLY_NACK:
- DRM_DEBUG_KMS("native nack (result=%d, size=%zu)\n", ret, msg->size);
+ DRM_DEBUG_DPCD("native nack (result=%d, size=%zu)\n", ret, msg->size);
return -EREMOTEIO;
case DP_AUX_NATIVE_REPLY_DEFER:
- DRM_DEBUG_KMS("native defer\n");
+ DRM_DEBUG_DPCD("native defer\n");
/*
* We could check for I2C bit rate capabilities and if
* available adjust this interval. We could also be
@@ -602,12 +642,12 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
return ret;
case DP_AUX_I2C_REPLY_NACK:
- DRM_DEBUG_KMS("I2C nack (result=%d, size=%zu\n", ret, msg->size);
+ DRM_DEBUG_DPCD("I2C nack (result=%d, size=%zu\n", ret, msg->size);
aux->i2c_nack_count++;
return -EREMOTEIO;
case DP_AUX_I2C_REPLY_DEFER:
- DRM_DEBUG_KMS("I2C defer\n");
+ DRM_DEBUG_DPCD("I2C defer\n");
/* DP Compliance Test 4.2.2.5 Requirement:
* Must have at least 7 retries for I2C defers on the
* transaction to pass this test
@@ -626,7 +666,7 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
}
}
- DRM_DEBUG_KMS("too many retries, giving up\n");
+ DRM_ERROR("I2C: too many retries, giving up\n");
return -EREMOTEIO;
}
@@ -654,7 +694,7 @@ static int drm_dp_i2c_drain_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *o
return err == 0 ? -EPROTO : err;
if (err < msg.size && err < ret) {
- DRM_DEBUG_KMS("Partial I2C reply: requested %zu bytes got %d bytes\n",
+ DRM_DEBUG_DPCD("Partial I2C reply: requested %zu bytes got %d bytes\n",
msg.size, err);
ret = err;
}
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 0a271ca..ac4d622 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -110,6 +110,8 @@ struct dma_buf_attachment;
* VBL: used for verbose debug message in the vblank code
* This is the category used by the DRM_DEBUG_VBL() macro.
*
+ * DPCD: used to log (displayport) DPCD messages
+ *
* Enabling verbose debug messages is done through the drm.debug parameter,
* each category being enabled by a bit.
*
@@ -117,7 +119,7 @@ struct dma_buf_attachment;
* drm.debug=0x2 will enable DRIVER messages
* drm.debug=0x3 will enable CORE and DRIVER messages
* ...
- * drm.debug=0x3f will enable all messages
+ * drm.debug=0x7f will enable all messages
*
* An interesting feature is that it's possible to enable verbose logging at
* run-time by echoing the debug value in its sysfs node:
@@ -129,6 +131,7 @@ struct dma_buf_attachment;
#define DRM_UT_PRIME 0x08
#define DRM_UT_ATOMIC 0x10
#define DRM_UT_VBL 0x20
+#define DRM_UT_DPCD 0x40
extern __printf(2, 3)
void drm_ut_debug_printk(const char *function_name,
@@ -226,6 +229,11 @@ void drm_err(const char *format, ...);
if (unlikely(drm_debug & DRM_UT_VBL)) \
drm_ut_debug_printk(__func__, fmt, ##args); \
} while (0)
+#define DRM_DEBUG_DPCD(fmt, args...) \
+ do { \
+ if (unlikely(drm_debug & DRM_UT_DPCD)) \
+ drm_ut_debug_printk(__func__, fmt, ##args); \
+ } while (0)
/*@}*/
--
2.5.0
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