drm/nouveau/disp: add conn method to query HPD pin status

And use it to bail early in DP detection and avoid futile AUX transactions.

This could be used on other connector types too in theory, but it's not
something we've ever done before and I'd rather not risk breaking working
systems without looking into it more closely.

It's safe for DP though.  We already do this by checking an AUX register
that contains HPD status and aborting the transaction.  However, this is
much deeper in the stack - after taking various mutexes, poking HW for no
good reason, and making a mess in debug logs.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/include/nvif/conn.h b/drivers/gpu/drm/nouveau/include/nvif/conn.h
index ad52cdafef183454cadc54475dfe3c51119b3378..f72a8f138f47f644bfb06ff4018e744d41b83a45 100644 (file)
--- a/drivers/gpu/drm/nouveau/include/nvif/conn.h
+++ b/drivers/gpu/drm/nouveau/include/nvif/conn.h
@@ -10,4 +10,9 @@ struct nvif_conn {
 
 int nvif_conn_ctor(struct nvif_disp *, const char *name, int id, struct nvif_conn *);
 void nvif_conn_dtor(struct nvif_conn *);
+
+#define NVIF_CONN_HPD_STATUS_UNSUPPORTED 0 /* negative if query fails */
+#define NVIF_CONN_HPD_STATUS_NOT_PRESENT 1
+#define NVIF_CONN_HPD_STATUS_PRESENT     2
+int nvif_conn_hpd_status(struct nvif_conn *);
 #endif

diff --git a/drivers/gpu/drm/nouveau/include/nvif/if0011.h b/drivers/gpu/drm/nouveau/include/nvif/if0011.h
index 9c910b29a730efca891af2478d3f47183cdc893f..04ba6581f840388103e93c32b94ecce6f75dff74 100644 (file)
--- a/drivers/gpu/drm/nouveau/include/nvif/if0011.h
+++ b/drivers/gpu/drm/nouveau/include/nvif/if0011.h
@@ -9,4 +9,15 @@ union nvif_conn_args {
                __u8 pad02[6];
        } v0;
 };
+
+#define NVIF_CONN_V0_HPD_STATUS 0x00000000
+
+union nvif_conn_hpd_status_args {
+       struct nvif_conn_hpd_status_v0 {
+               __u8 version;
+               __u8 support;
+               __u8 present;
+               __u8 pad03[5];
+       } v0;
+};
 #endif

diff --git a/drivers/gpu/drm/nouveau/nouveau_dp.c b/drivers/gpu/drm/nouveau/nouveau_dp.c
index c36f510d5d4cb5c04468811b78c40e9374b65ecd..20db8ea1a0baf377a3b0643f3c3973a4e21006b5 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_dp.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dp.c
@@ -107,7 +107,7 @@ nouveau_dp_detect(struct nouveau_connector *nv_connector,
        struct nv50_mstm *mstm = nv_encoder->dp.mstm;
        enum drm_connector_status status;
        u8 *dpcd = nv_encoder->dp.dpcd;
-       int ret = NOUVEAU_DP_NONE;
+       int ret = NOUVEAU_DP_NONE, hpd;
 
        /* If we've already read the DPCD on an eDP device, we don't need to
         * reread it as it won't change
@@ -133,6 +133,16 @@ nouveau_dp_detect(struct nouveau_connector *nv_connector,
                }
        }
 
+       /* Check status of HPD pin before attempting an AUX transaction that
+        * would result in a number of (futile) retries on a connector which
+        * has no display plugged.
+        *
+        * TODO: look into checking this before probing I2C to detect DVI/HDMI
+        */
+       hpd = nvif_conn_hpd_status(&nv_connector->conn);
+       if (hpd == NVIF_CONN_HPD_STATUS_NOT_PRESENT)
+               goto out;
+
        status = nouveau_dp_probe_dpcd(nv_connector, nv_encoder);
        if (status == connector_status_disconnected)
                goto out;

diff --git a/drivers/gpu/drm/nouveau/nvif/conn.c b/drivers/gpu/drm/nouveau/nvif/conn.c
index a83b8a4a57e6220e8a0dc5d0be607eda9c715037..4ce935d58c906f4abe6dad6dfa75b1009642061b 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvif/conn.c
+++ b/drivers/gpu/drm/nouveau/nvif/conn.c
@@ -26,6 +26,20 @@
 #include <nvif/class.h>
 #include <nvif/if0011.h>
 
+int
+nvif_conn_hpd_status(struct nvif_conn *conn)
+{
+       struct nvif_conn_hpd_status_v0 args;
+       int ret;
+
+       args.version = 0;
+
+       ret = nvif_mthd(&conn->object, NVIF_CONN_V0_HPD_STATUS, &args, sizeof(args));
+       NVIF_ERRON(ret, &conn->object, "[HPD_STATUS] support:%d present:%d",
+                  args.support, args.present);
+       return ret ? ret : !!args.support + !!args.present;
+}
+
 void
 nvif_conn_dtor(struct nvif_conn *conn)
 {

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/conn.c b/drivers/gpu/drm/nouveau/nvkm/engine/disp/conn.c
index febc5c2744884413947b6501c8f3b52911d944ce..7ed11801a3ae6951fd6946a41087a1ab9c7a565b 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/conn.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/conn.c
@@ -86,6 +86,7 @@ nvkm_conn_ctor(struct nvkm_disp *disp, int index, struct nvbios_connE *info,
        conn->disp = disp;
        conn->index = index;
        conn->info = *info;
+       conn->info.hpd = DCB_GPIO_UNUSED;
 
        CONN_DBG(conn, "type %02x loc %d hpd %02x dp %x di %x sr %x lcdid %x",
                 info->type, info->location, info->hpd, info->dp,
@@ -100,11 +101,12 @@ nvkm_conn_ctor(struct nvkm_disp *disp, int index, struct nvbios_connE *info,
 
                ret = nvkm_gpio_find(gpio, 0, info->hpd, DCB_GPIO_UNUSED, &func);
                if (ret) {
-                       CONN_ERR(conn, "func %02x lookup failed, %d",
-                                info->hpd, ret);
+                       CONN_ERR(conn, "func %02x lookup failed, %d", info->hpd, ret);
                        return;
                }
 
+               conn->info.hpd = func.line;
+
                ret = nvkm_notify_init(NULL, &gpio->event, nvkm_conn_hpd,
                                       true, &(struct nvkm_gpio_ntfy_req) {
                                        .mask = NVKM_GPIO_TOGGLED,

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/uconn.c b/drivers/gpu/drm/nouveau/nvkm/engine/disp/uconn.c
index 3fbbb6e6a66b3e55a8feca2ea7cc2ca2dd8ff2a0..fd9f18144c26599e5f18c5cae561b7ad39c6b113 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/uconn.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/uconn.c
@@ -22,8 +22,50 @@
 #define nvkm_uconn(p) container_of((p), struct nvkm_conn, object)
 #include "conn.h"
 
+#include <subdev/gpio.h>
+
 #include <nvif/if0011.h>
 
+static int
+nvkm_uconn_mthd_hpd_status(struct nvkm_conn *conn, void *argv, u32 argc)
+{
+       struct nvkm_gpio *gpio = conn->disp->engine.subdev.device->gpio;
+       union nvif_conn_hpd_status_args *args = argv;
+
+       if (argc != sizeof(args->v0) || args->v0.version != 0)
+               return -ENOSYS;
+
+       args->v0.support = gpio && conn->info.hpd != DCB_GPIO_UNUSED;
+       args->v0.present = 0;
+
+       if (args->v0.support) {
+               int ret = nvkm_gpio_get(gpio, 0, DCB_GPIO_UNUSED, conn->info.hpd);
+
+               if (WARN_ON(ret < 0)) {
+                       args->v0.support = false;
+                       return 0;
+               }
+
+               args->v0.present = ret;
+       }
+
+       return 0;
+}
+
+static int
+nvkm_uconn_mthd(struct nvkm_object *object, u32 mthd, void *argv, u32 argc)
+{
+       struct nvkm_conn *conn = nvkm_uconn(object);
+
+       switch (mthd) {
+       case NVIF_CONN_V0_HPD_STATUS: return nvkm_uconn_mthd_hpd_status(conn, argv, argc);
+       default:
+               break;
+       }
+
+       return -EINVAL;
+}
+
 static void *
 nvkm_uconn_dtor(struct nvkm_object *object)
 {
@@ -39,6 +81,7 @@ nvkm_uconn_dtor(struct nvkm_object *object)
 static const struct nvkm_object_func
 nvkm_uconn = {
        .dtor = nvkm_uconn_dtor,
+       .mthd = nvkm_uconn_mthd,
 };
 
 int