On Tue, Jul 31, 2018 at 05:39:26AM -0700, Tejas Upadhyay wrote:
Patch adds support for debugging DisplayPort :
- All dpcd read/write transactions are logged
- Logging done per AUX interface
- Use following command to to list AUX transactions:
Hi Tejas, Thanks for your patch. We already have this information going to the logs via the DRM_DEBUG_KMS() prints in the i2c-over-aux function and via the drm_dp_dump_access() function in the native read/write functions. So you should be able to access this information already by writing 0x100 to drm.debug module param.
Does that satisfy your requirements?
Sean
bash # cat /sys/kernel/debug/drm_dp_aux/$AUXNAME @0x0000: 0x12 @0x0001: 0x14 @0x0002: 0xc4 @0x0003: 0x01 @0x0004: 0x01 @0x0005: 0x01 @0x0006: 0x01 @0x0007: 0x81 @0x0008: 0x02 @0x0009: 0x02 @0x000a: 0x06 @0x000b: 0x00 @0x000c: 0x00 @0x000d: 0x00 @0x000e: 0x00 @0x0100: 0x14 @0x0101: 0x82 @0x0102: 0x00 @0x0103: 0x0a @0x0104: 0x0a @0x0107: 0x10 @0x0108: 0x01 @0x0202: 0x77 @0x0203: 0x00 @0x0204: 0x01 @0x0205: 0x02 @0x0206: 0x66 @0x0207: 0x00
Above information will help to debug DisplayPort related runtime issues knowing what communication was done between DisplayPort sink and source.
Signed-off-by: Tejas Upadhyay tejas.upadhyay@xilinx.com Signed-off-by: Hyun Kwon hyun.kwon@xilinx.com
drivers/gpu/drm/Kconfig | 10 +++ drivers/gpu/drm/drm_dp_helper.c | 174 +++++++++++++++++++++++++++++++++++++++- include/drm/drm_dp_helper.h | 7 ++ 3 files changed, 190 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index f3c71e3..bb16e24 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -34,6 +34,16 @@ config DRM_DP_AUX_CHARDEV read and write values to arbitrary DPCD registers on the DP aux channel.
+config DRM_DEBUG_DP
bool "DRM dp debug helper"default ndepends on DRMhelpChoose this option to enable a debugfs functionality for drm-dp.Will help in debugging display port related issue.Recommended for driver developer as well as tester.Say "Y" to enable debug support.config DRM_DEBUG_MM bool "Insert extra checks and debug info into the DRM range managers" default n diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 08af8d6..e8be361 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -28,6 +28,9 @@ #include <linux/sched.h> #include <linux/i2c.h> #include <linux/seq_file.h> +#ifdef CONFIG_DRM_DEBUG_DP +#include <linux/debugfs.h> +#endif #include <drm/drm_dp_helper.h> #include <drm/drmP.h>
@@ -57,6 +60,171 @@ static u8 dp_get_lane_status(const u8 link_status[DP_LINK_STATUS_SIZE], return (l >> s) & 0xf; }
+#ifdef CONFIG_DRM_DEBUG_DP
+static uint drm_dp_debugfs_dpcd_size = 0x5ff; +module_param_named(debugfs_dpcd_size, drm_dp_debugfs_dpcd_size, uint, 0444); +MODULE_PARM_DESC(debugfs_dpcd_size, "Debugfs DPCD buffer size (default: 1544)");
+static struct dentry *root;
+static bool drm_dp_debugfs_bitmap_is_set(struct drm_dp_aux *aux,
unsigned int pos)+{
u8 byte, bit;byte = pos / 8;bit = pos % 8;return !!(aux->dpcd_bitmap[byte] & BIT(bit));+}
+static void drm_dp_debugfs_bitmap_set(struct drm_dp_aux *aux, unsigned int pos) +{
u8 byte, bit;byte = pos / 8;bit = pos % 8;aux->dpcd_bitmap[byte] |= BIT(bit);+}
+/* DP debugfs read API, to be called by user app */ +static ssize_t drm_dp_debugfs_read(struct file *f, char __user *buf,
size_t size, loff_t *pos)+{
struct drm_dp_aux *aux = (struct drm_dp_aux *)f->f_inode->i_private;char *kern_buff = NULL;unsigned int i;size_t kern_buff_len;int err;if (size <= 0)return -EINVAL;if (*pos != 0)return 0;kern_buff_len = size;kern_buff = kzalloc(kern_buff_len, GFP_KERNEL);if (!kern_buff)return -ENOMEM;for (i = 0; i < drm_dp_debugfs_dpcd_size; i++) {if (drm_dp_debugfs_bitmap_is_set(aux, i)) {char str[16] = "";sprintf(str, "@0x%04x: 0x%02x\n", i, aux->dpcd_data[i]);if (kern_buff_len < strlen(str))break;strcat(kern_buff, str);kern_buff_len -= strlen(str);}}kern_buff_len = strlen(kern_buff);size = min(size, kern_buff_len);err = copy_to_user(buf, kern_buff, size);kfree(kern_buff);if (err)return err;*pos = size + 1;return size;+}
+static const struct file_operations fops_drm_dp_dbgfs = {
.owner = THIS_MODULE,.read = drm_dp_debugfs_read,+};
+static int drm_dp_debugfs_init(struct drm_dp_aux *aux) +{
struct dentry *entry;u8 *bitmap, *data;int err;/* FIXME: better be under drm debugfs dir, and cleaned up properly */if (!root) {root = debugfs_create_dir("drm_dp_aux", NULL);if (!root) {DRM_ERROR("debugfs_create_dir failed for root\n");return -ENODEV;}}/* FIXME: There may be a better name than the aux name */entry = debugfs_create_file(aux->name, 0444, root, aux,&fops_drm_dp_dbgfs);if (!entry) {DRM_ERROR("debugfs_create_file testcase failed\n");err = -ENODEV;goto err_dbgfs;}bitmap = devm_kzalloc(aux->dev,sizeof(*bitmap) * (drm_dp_debugfs_dpcd_size / 8),GFP_KERNEL);if (unlikely(!bitmap)) {err = -ENOMEM;goto err_dbgfs;}data = devm_kzalloc(aux->dev, sizeof(*data) * drm_dp_debugfs_dpcd_size,GFP_KERNEL);if (unlikely(!data)) {err = -ENOMEM;goto err_dbgfs;}aux->dpcd_data = data;aux->dpcd_bitmap = bitmap;return 0;+err_dbgfs:
debugfs_remove_recursive(entry);return err;+}
+/* Deinit DP debugfs */ +static void drm_dp_debugfs_deinit(struct drm_dp_aux *aux) +{
struct dentry *entry;entry = debugfs_lookup(aux->name, root);debugfs_remove_recursive(entry);+}
+static void drm_dp_debugfs_log(struct drm_dp_aux *aux,
struct drm_dp_aux_msg *msg)+{
u8 *buf;unsigned int i;buf = (u8 *)msg->buffer;for (i = 0; i < msg->size; i++) {aux->dpcd_data[msg->address + i] = buf[i];drm_dp_debugfs_bitmap_set(aux, msg->address + i);}+}
+#else
+static void drm_dp_debugfs_log(struct drm_dp_aux *aux,
struct drm_dp_aux_msg *msg)+{ +}
+static int drm_dp_debugfs_init(struct drm_dp_aux *aux) +{
return 0;+}
+static void drm_dp_debugfs_deinit(struct drm_dp_aux *aux) +{ +}
+#endif
bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE], int lane_count) { @@ -229,6 +397,8 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request, ret = err;
unlock:
/* Log dpcd aux write transactions*/drm_dp_debugfs_log(aux, &msg); mutex_unlock(&aux->hw_mutex); return ret;} @@ -1108,7 +1278,8 @@ int drm_dp_aux_register(struct drm_dp_aux *aux) drm_dp_aux_unregister_devnode(aux); return ret; }
/* Init DP debufs*/drm_dp_debugfs_init(aux); return 0;} EXPORT_SYMBOL(drm_dp_aux_register); @@ -1119,6 +1290,7 @@ EXPORT_SYMBOL(drm_dp_aux_register); */ void drm_dp_aux_unregister(struct drm_dp_aux *aux) {
drm_dp_debugfs_deinit(aux); drm_dp_aux_unregister_devnode(aux); i2c_del_adapter(&aux->ddc);} diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index b17476a..442dfb8 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -962,6 +962,8 @@ struct drm_dp_aux_msg {
- @crc_work: worker that captures CRCs for each frame
- @crc_count: counter of captured frame CRCs
- @transfer: transfers a message representing a single AUX transaction
- @dpcd_data: store aux transactions for dp debugfs
- @dpcd_bitmap: store a bitmap for valid dpcd data
- The .dev field should be set to a pointer to the device that implements
- the AUX channel.
@@ -1010,6 +1012,11 @@ struct drm_dp_aux { * @i2c_defer_count: Counts I2C DEFERs, used for DP validation. */ unsigned i2c_defer_count; +#ifdef CONFIG_DRM_DEBUG_DP
/* aux transactions for dp debugfs*/u8 *dpcd_data;u8 *dpcd_bitmap;+#endif };
ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset,
2.7.4
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