nouveau/dp: handle retries for AUX CH transfers with GSP.

eb284f4 drm/nouveau/dp: Honor GSP link training retry timeouts

tried to fix a problem with panel retires, however it appears
the auxch also needs the same treatment, so add the same retry
wrapper around it.

This fixes some eDP panels after a suspend/resume cycle.

Fixes: eb284f4 ("drm/nouveau/dp: Honor GSP link training retry timeouts")
Cc: stable@vger.kernel.org
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241111034126.2028401-2-airlied@gmail.com

drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c

@@ -1060,33 +1060,44 @@ r535_dp_aux_xfer(struct nvkm_outp *outp, u8 type, u32 addr, u8 *data, u8 *psize)
 	NV0073_CTRL_DP_AUXCH_CTRL_PARAMS *ctrl;
 	u8 size = *psize;
 	int ret;
+	int retries;
 
-	ctrl = nvkm_gsp_rm_ctrl_get(&disp->rm.objcom, NV0073_CTRL_CMD_DP_AUXCH_CTRL, sizeof(*ctrl));
-	if (IS_ERR(ctrl))
-		return PTR_ERR(ctrl);
+	for (retries = 0; retries < 3; ++retries) {
+		ctrl = nvkm_gsp_rm_ctrl_get(&disp->rm.objcom, NV0073_CTRL_CMD_DP_AUXCH_CTRL, sizeof(*ctrl));
+		if (IS_ERR(ctrl))
+			return PTR_ERR(ctrl);
 
-	ctrl->subDeviceInstance = 0;
-	ctrl->displayId = BIT(outp->index);
-	ctrl->bAddrOnly = !size;
-	ctrl->cmd = type;
-	if (ctrl->bAddrOnly) {
-		ctrl->cmd = NVDEF_SET(ctrl->cmd, NV0073_CTRL, DP_AUXCH_CMD, REQ_TYPE, WRITE);
-		ctrl->cmd = NVDEF_SET(ctrl->cmd, NV0073_CTRL, DP_AUXCH_CMD,  I2C_MOT, FALSE);
-	}
-	ctrl->addr = addr;
-	ctrl->size = !ctrl->bAddrOnly ? (size - 1) : 0;
-	memcpy(ctrl->data, data, size);
+		ctrl->subDeviceInstance = 0;
+		ctrl->displayId = BIT(outp->index);
+		ctrl->bAddrOnly = !size;
+		ctrl->cmd = type;
+		if (ctrl->bAddrOnly) {
+			ctrl->cmd = NVDEF_SET(ctrl->cmd, NV0073_CTRL, DP_AUXCH_CMD, REQ_TYPE, WRITE);
+			ctrl->cmd = NVDEF_SET(ctrl->cmd, NV0073_CTRL, DP_AUXCH_CMD,  I2C_MOT, FALSE);
+		}
+		ctrl->addr = addr;
+		ctrl->size = !ctrl->bAddrOnly ? (size - 1) : 0;
+		memcpy(ctrl->data, data, size);
 
-	ret = nvkm_gsp_rm_ctrl_push(&disp->rm.objcom, &ctrl, sizeof(*ctrl));
-	if (ret) {
-		nvkm_gsp_rm_ctrl_done(&disp->rm.objcom, ctrl);
-		return ret;
+		ret = nvkm_gsp_rm_ctrl_push(&disp->rm.objcom, &ctrl, sizeof(*ctrl));
+		if ((ret == -EAGAIN || ret == -EBUSY) && ctrl->retryTimeMs) {
+			/*
+			 * Device (likely an eDP panel) isn't ready yet, wait for the time specified
+			 * by GSP before retrying again
+			 */
+			nvkm_debug(&disp->engine.subdev,
+				   "Waiting %dms for GSP LT panel delay before retrying in AUX\n",
+				   ctrl->retryTimeMs);
+			msleep(ctrl->retryTimeMs);
+			nvkm_gsp_rm_ctrl_done(&disp->rm.objcom, ctrl);
+		} else {
+			memcpy(data, ctrl->data, size);
+			*psize = ctrl->size;
+			ret = ctrl->replyType;
+			nvkm_gsp_rm_ctrl_done(&disp->rm.objcom, ctrl);
+			break;
+		}
 	}
-
-	memcpy(data, ctrl->data, size);
-	*psize = ctrl->size;
-	ret = ctrl->replyType;
-	nvkm_gsp_rm_ctrl_done(&disp->rm.objcom, ctrl);
 	return ret;
 }