On 10/19/2020 4:07 AM, Shankar, Uma wrote:
-----Original Message----- From: Nautiyal, Ankit K ankit.k.nautiyal@intel.com Sent: Thursday, October 15, 2020 4:23 PM To: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org; Shankar, Uma uma.shankar@intel.com; Kulkarni, Vandita vandita.kulkarni@intel.com; ville.syrjala@linux.intel.com; Sharma, Swati2 swati2.sharma@intel.com Subject: [RFC 07/13] drm/dp_helper: Add support for link status and link recovery
Move this in the start of the series along with rest of the generic DRM helpers.
Alight, will move this along with other DRM helpers.
From: Swati Sharma swati2.sharma@intel.com
This patch adds support for link status and link recovery. There are specific DPCD’s defined for link status check and recovery in case of any issues. PCON will communicate the same using an IRQ_HPD to source. HDMI sink would have indicated the same to PCON using SCDC interrupt mechanism. While source can always read final HDMI sink’s status using I2C over AUX, it’s easier and faster to read the PCON’s already read HDMI sink’s status registers.
Signed-off-by: Swati Sharma swati2.sharma@intel.com Signed-off-by: Ankit Nautiyal ankit.k.nautiyal@intel.com
drivers/gpu/drm/drm_dp_helper.c | 33 +++++++++++++++++++++++++++++++++ include/drm/drm_dp_helper.h | 16 ++++++++++++++++ 2 files changed, 49 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index df858533dbf7..33a4ac2fb225 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -2896,3 +2896,36 @@ int drm_dp_pcon_hdmi_link_mode(struct drm_dp_aux *aux, u8 *frl_trained_mask) return mode; } EXPORT_SYMBOL(drm_dp_pcon_hdmi_link_mode);
+void drm_dp_pcon_hdmi_frl_link_error_count(struct drm_dp_aux *aux,
- struct drm_connector *connector) {
This just prints a message if error counts are detected. There isn't any recovery here. May be you should re-phrase the patch header and description to reflect the same.
Also what will be the usage of this just prints a message, may be return the error to caller to plan a recovery or link reset .
You are right, this patch is just adding few DPCDs that will be useful in detection of Link failure.
These registers will be used while servicing short pulse IRQ_HPD and there the FRL training will be restarted. In case of failure, will be switched to TMDS mode.
This is taken care in the subsequent patch for i915, which modifies the intel_dp_short_pulse().
The helper function is more for debugging purpose, to identify the exact lanes which had issues and the magnitude of the error counts in that lane.
I will rephrase the commit message to be more clear.
+u8 buf, error_count; +int i, num_error; +struct drm_hdmi_info *hdmi = &connector->display_info.hdmi;
+for (i = 0; i < hdmi->max_lanes; i++) +{ +if (drm_dp_dpcd_readb(aux, DP_PCON_HDMI_ERROR_STATUS_LN0 + i , &buf) < 0) +return;
+error_count = buf & DP_PCON_HDMI_ERROR_COUNT_MASK;
+switch(error_count) {
Alignment is off.
Agreed. Will fix this in next version.
+case DP_PCON_HDMI_ERROR_COUNT_HUNDRED_PLUS: +num_error = 100; +break; +case DP_PCON_HDMI_ERROR_COUNT_TEN_PLUS: +num_error = 10; +break; +case DP_PCON_HDMI_ERROR_COUNT_THREE_PLUS: +num_error = 3; +break; +default: +num_error = 0; +}
+DRM_ERROR("More than %d errors since the last read for lane %d", num_error, i); +} +} +EXPORT_SYMBOL(drm_dp_pcon_hdmi_frl_link_error_count); diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index d6f79b2d1287..eb26c86dc8ca 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -946,6 +946,11 @@ struct drm_device; # define DP_CEC_IRQ (1 << 2)
#define DP_LINK_SERVICE_IRQ_VECTOR_ESI0 0x2005 /* 1.2 */ +# define RX_CAP_CHANGED (1 << 0) +# define LINK_STATUS_CHANGED (1 << 1) +# define STREAM_STATUS_CHANGED (1 << 2) +# define HDMI_LINK_STATUS_CHANGED (1 << 3) +# define CONNECTED_OFF_ENTRY_REQUESTED (1 << 4)
#define DP_PSR_ERROR_STATUS 0x2006 /* XXX 1.2? */ # define DP_PSR_LINK_CRC_ERROR (1 << 0) @@ -1130,6 +1135,16 @@ struct drm_device; #define DP_PROTOCOL_CONVERTER_CONTROL_20x3052 /* DP 1.3 */ # define DP_CONVERSION_TO_YCBCR422_ENABLE(1 << 0) /* DP 1.3 */
+/* PCON Downstream HDMI ERROR Status per Lane */ +#define DP_PCON_HDMI_ERROR_STATUS_LN0 0x3037 +#define DP_PCON_HDMI_ERROR_STATUS_LN1 0x3038 +#define DP_PCON_HDMI_ERROR_STATUS_LN2 0x3039 +#define DP_PCON_HDMI_ERROR_STATUS_LN3 0x303A +# define DP_PCON_HDMI_ERROR_COUNT_MASK (0x7 << 0) +# define DP_PCON_HDMI_ERROR_COUNT_THREE_PLUS (1 << 0) +# define DP_PCON_HDMI_ERROR_COUNT_TEN_PLUS (1 << 1) +# define DP_PCON_HDMI_ERROR_COUNT_HUNDRED_PLUS (1 << 2)
- /* HDCP 1.3 and HDCP 2.2 */ #define DP_AUX_HDCP_BKSV0x68000 #define DP_AUX_HDCP_RI_PRIME0x68005
@@ -2047,4 +2062,5 @@ int drm_dp_pcon_frl_enable(struct drm_dp_aux *aux);
bool drm_dp_pcon_hdmi_link_active(struct drm_dp_aux *aux); int drm_dp_pcon_hdmi_link_mode(struct drm_dp_aux *aux, u8 *frl_trained_mask); +void drm_dp_pcon_hdmi_frl_link_error_count(struct drm_dp_aux *aux, +struct drm_connector *connector);
Leave a blank line.
Agreed. Will fix this in next version.
Thanks & Regards,
Ankit
#endif /* _DRM_DP_HELPER_H_ */
2.17.1