diff options
Diffstat (limited to 'drivers/gpu/drm/drm_dp_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_dp_helper.c | 191 |
1 files changed, 188 insertions, 3 deletions
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index eae5ef963cb7..ac3924a877e0 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -27,10 +27,12 @@ #include <linux/errno.h> #include <linux/sched.h> #include <linux/i2c.h> +#include <linux/seq_file.h> #include <drm/drm_dp_helper.h> -#include <drm/drm_dp_aux_dev.h> #include <drm/drmP.h> +#include "drm_crtc_helper_internal.h" + /** * DOC: dp helpers * @@ -223,7 +225,7 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request, err = ret; } - DRM_DEBUG_KMS("too many retries, giving up\n"); + DRM_DEBUG_KMS("Too many retries, giving up. First error: %d\n", err); ret = err; unlock: @@ -438,6 +440,179 @@ int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link) } EXPORT_SYMBOL(drm_dp_link_configure); +/** + * drm_dp_downstream_max_clock() - extract branch device max + * pixel rate for legacy VGA + * converter or max TMDS clock + * rate for others + * @dpcd: DisplayPort configuration data + * @port_cap: port capabilities + * + * Returns max clock in kHz on success or 0 if max clock not defined + */ +int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], + const u8 port_cap[4]) +{ + int type = port_cap[0] & DP_DS_PORT_TYPE_MASK; + bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] & + DP_DETAILED_CAP_INFO_AVAILABLE; + + if (!detailed_cap_info) + return 0; + + switch (type) { + case DP_DS_PORT_TYPE_VGA: + return port_cap[1] * 8 * 1000; + case DP_DS_PORT_TYPE_DVI: + case DP_DS_PORT_TYPE_HDMI: + case DP_DS_PORT_TYPE_DP_DUALMODE: + return port_cap[1] * 2500; + default: + return 0; + } +} +EXPORT_SYMBOL(drm_dp_downstream_max_clock); + +/** + * drm_dp_downstream_max_bpc() - extract branch device max + * bits per component + * @dpcd: DisplayPort configuration data + * @port_cap: port capabilities + * + * Returns max bpc on success or 0 if max bpc not defined + */ +int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], + const u8 port_cap[4]) +{ + int type = port_cap[0] & DP_DS_PORT_TYPE_MASK; + bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] & + DP_DETAILED_CAP_INFO_AVAILABLE; + int bpc; + + if (!detailed_cap_info) + return 0; + + switch (type) { + case DP_DS_PORT_TYPE_VGA: + case DP_DS_PORT_TYPE_DVI: + case DP_DS_PORT_TYPE_HDMI: + case DP_DS_PORT_TYPE_DP_DUALMODE: + bpc = port_cap[2] & DP_DS_MAX_BPC_MASK; + + switch (bpc) { + case DP_DS_8BPC: + return 8; + case DP_DS_10BPC: + return 10; + case DP_DS_12BPC: + return 12; + case DP_DS_16BPC: + return 16; + } + default: + return 0; + } +} +EXPORT_SYMBOL(drm_dp_downstream_max_bpc); + +/** + * drm_dp_downstream_id() - identify branch device + * @aux: DisplayPort AUX channel + * @id: DisplayPort branch device id + * + * Returns branch device id on success or NULL on failure + */ +int drm_dp_downstream_id(struct drm_dp_aux *aux, char id[6]) +{ + return drm_dp_dpcd_read(aux, DP_BRANCH_ID, id, 6); +} +EXPORT_SYMBOL(drm_dp_downstream_id); + +/** + * drm_dp_downstream_debug() - debug DP branch devices + * @m: pointer for debugfs file + * @dpcd: DisplayPort configuration data + * @port_cap: port capabilities + * @aux: DisplayPort AUX channel + * + */ +void drm_dp_downstream_debug(struct seq_file *m, + const u8 dpcd[DP_RECEIVER_CAP_SIZE], + const u8 port_cap[4], struct drm_dp_aux *aux) +{ + bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] & + DP_DETAILED_CAP_INFO_AVAILABLE; + int clk; + int bpc; + char id[6]; + int len; + uint8_t rev[2]; + int type = port_cap[0] & DP_DS_PORT_TYPE_MASK; + bool branch_device = dpcd[DP_DOWNSTREAMPORT_PRESENT] & + DP_DWN_STRM_PORT_PRESENT; + + seq_printf(m, "\tDP branch device present: %s\n", + branch_device ? "yes" : "no"); + + if (!branch_device) + return; + + switch (type) { + case DP_DS_PORT_TYPE_DP: + seq_puts(m, "\t\tType: DisplayPort\n"); + break; + case DP_DS_PORT_TYPE_VGA: + seq_puts(m, "\t\tType: VGA\n"); + break; + case DP_DS_PORT_TYPE_DVI: + seq_puts(m, "\t\tType: DVI\n"); + break; + case DP_DS_PORT_TYPE_HDMI: + seq_puts(m, "\t\tType: HDMI\n"); + break; + case DP_DS_PORT_TYPE_NON_EDID: + seq_puts(m, "\t\tType: others without EDID support\n"); + break; + case DP_DS_PORT_TYPE_DP_DUALMODE: + seq_puts(m, "\t\tType: DP++\n"); + break; + case DP_DS_PORT_TYPE_WIRELESS: + seq_puts(m, "\t\tType: Wireless\n"); + break; + default: + seq_puts(m, "\t\tType: N/A\n"); + } + + drm_dp_downstream_id(aux, id); + seq_printf(m, "\t\tID: %s\n", id); + + len = drm_dp_dpcd_read(aux, DP_BRANCH_HW_REV, &rev[0], 1); + if (len > 0) + seq_printf(m, "\t\tHW: %d.%d\n", + (rev[0] & 0xf0) >> 4, rev[0] & 0xf); + + len = drm_dp_dpcd_read(aux, DP_BRANCH_SW_REV, &rev, 2); + if (len > 0) + seq_printf(m, "\t\tSW: %d.%d\n", rev[0], rev[1]); + + if (detailed_cap_info) { + clk = drm_dp_downstream_max_clock(dpcd, port_cap); + + if (clk > 0) { + if (type == DP_DS_PORT_TYPE_VGA) + seq_printf(m, "\t\tMax dot clock: %d kHz\n", clk); + else + seq_printf(m, "\t\tMax TMDS clock: %d kHz\n", clk); + } + + bpc = drm_dp_downstream_max_bpc(dpcd, port_cap); + + if (bpc > 0) + seq_printf(m, "\t\tMax bpc: %d\n", bpc); + } +} +EXPORT_SYMBOL(drm_dp_downstream_debug); + /* * I2C-over-AUX implementation */ @@ -574,7 +749,17 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) if (ret == -EBUSY) continue; - DRM_DEBUG_KMS("transaction failed: %d\n", ret); + /* + * While timeouts can be errors, they're usually normal + * behavior (for instance, when a driver tries to + * communicate with a non-existant DisplayPort device). + * Avoid spamming the kernel log with timeout errors. + */ + if (ret == -ETIMEDOUT) + DRM_DEBUG_KMS_RATELIMITED("transaction timed out\n"); + else + DRM_DEBUG_KMS("transaction failed: %d\n", ret); + return ret; } |