[PATCH 2/2] nouveau/dp: handle retries for AUX CH transfers with GSP.

[Ben Skeggs]

On 11/11/24 13:41, Dave Airlie wrote:

> From: Dave Airlie <airlied at redhat.com>
>
> eb284f4b3781 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.

This works fine on my laptop (though it doesn't fix the issues I see 
there unfortunately).

The handling of -EAGAIN can be removed here too, but aside from that:

Reviewed-by: Ben Skeggs <bskeggs at nvidia.com>

>
> Fixes: eb284f4b3781 ("drm/nouveau/dp: Honor GSP link training retry timeouts")
> Signed-off-by: Dave Airlie <airlied at redhat.com>
> ---
>   .../gpu/drm/nouveau/nvkm/engine/disp/r535.c   | 57 +++++++++++--------
>   1 file changed, 34 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c b/drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c
> index 8f9aa3463c3c..99110ab2f44d 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c
> +++ b/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;
>   }
>