Hans, I am almost done with my review comment but I am stuck here. Benoit Parrot <bparrot@xxxxxx> wrote on Tue [2015-Jun-23 14:36:47 -0500]: > > > + > > > +static int cal_get_external_info(struct cal_ctx *ctx) > > > +{ > > > + struct v4l2_ext_control ctrl_ext; > > > + struct v4l2_ext_controls ctrls_ext; > > > + int ret; > > > + > > > + ctx_dbg(3, ctx, "%s\n", __func__); > > > + > > > + memset(&ctrls_ext, 0, sizeof(ctrls_ext)); > > > + memset(&ctrl_ext, 0, sizeof(ctrl_ext)); > > > + > > > + ctrl_ext.id = V4L2_CID_PIXEL_RATE; > > > + > > > + ctrls_ext.count = 1; > > > + ctrls_ext.controls = &ctrl_ext; > > > + > > > + ret = v4l2_g_ext_ctrls(&ctx->ctrl_handler, &ctrls_ext); > > > > Use v4l2_ctrl_g_ctrl_int64() instead: much simpler. You do need to store the > > v4l2_ctrl pointer for the pixel rate control when you create it, but that's no > > problem. (or use v4l2_ctrl_find, but I prefer to just cache the pointer). > > Hmm, that's how I had it in our local 3.14 branch originally but I kept > getting 0 instead of the actual pixel rate. > I'll revert it back and test again against linux-media/master. > > > > > > + if (ret < 0) { > > > + ctx_err(ctx, "no pixel rate control in subdev: %s\n", > > > + ctx->sensor->name); > > > + return -EPIPE; > > > + } > > > + > > > + ctx->external_rate = ctrl_ext.value64; > > > + ctx_dbg(3, ctx, "sensor Pixel Rate: %d\n", ctx->external_rate); > > > + > > > + return 0; > > > +} Alright, in order to comply with this comment I rewrote the above function as follows: static int cal_get_external_info(struct cal_ctx *ctx) { struct v4l2_ctrl *ctrl; s64 val; ctx_dbg(3, ctx, "%s\n", __func__); ctrl = v4l2_ctrl_find(&ctx->ctrl_handler, V4L2_CID_PIXEL_RATE); // ctrl = v4l2_ctrl_find(ctx->sensor->ctrl_handler, V4L2_CID_PIXEL_RATE); if (ctrl == NULL) { ctx_err(ctx, "no pixel rate control in subdev: %s\n", ctx->sensor->name); return -EPIPE; } // ctx->external_rate = v4l2_ctrl_g_ctrl_int64(ctrl); val = v4l2_ctrl_g_ctrl_int64(ctrl); ctx_dbg(3, ctx, "sensor Pixel Rate: s64 %lld\n", val); ctx->external_rate = (unsigned int)val; ctx_dbg(3, ctx, "sensor Pixel Rate: %d\n", ctx->external_rate); return 0; } But in all cases the value I get from v4l2_ctrl_g_ctrl_int64 is always zero! Now I have tripple check with debug code that the subdev is in fact setting the p_cur and p_new value to something useful (i.e. not 0). I have traced it down to the get_ctrl() call inside of v4l2_ctrl_g_ctrl_int64. static int get_ctrl(struct v4l2_ctrl *ctrl, struct v4l2_ext_control *c) { struct v4l2_ctrl *master = ctrl->cluster[0]; int ret = 0; int i; printk("BENOIT: ==> get_ctrl: ctrl name:%s cur: %lld new: %lld\n", ctrl->name, *ctrl->p_cur.p_s64, *ctrl->p_new.p_s64); /* Compound controls are not supported. The new_to_user() and * cur_to_user() calls below would need to be modified not to access * userspace memory when called from get_ctrl(). */ printk("BENOIT: ==> get_ctrl: ctrl name:%s is_int: %d\n", ctrl->name, ctrl->is_int); if (!ctrl->is_int) return -EINVAL; **** It always exits here, because for int64_integer the is_int is not set! **** which means on the way back out the value reported will always be 0! printk("BENOIT: ==> get_ctrl: ctrl name:%s flags: 0x%08lx\n", ctrl->name, ctrl->flags); if (ctrl->flags & V4L2_CTRL_FLAG_WRITE_ONLY) return -EACCES; printk("BENOIT: ==> get_ctrl: ctrl name:%s before ctrl_lock:\n", ctrl->name); v4l2_ctrl_lock(master); /* g_volatile_ctrl will update the current control values */ if (ctrl->flags & V4L2_CTRL_FLAG_VOLATILE) { for (i = 0; i < master->ncontrols; i++) cur_to_new(master->cluster[i]); ret = call_op(master, g_volatile_ctrl); new_to_user(c, ctrl); } else { cur_to_user(c, ctrl); } printk("BENOIT: <== get_ctrl: ctrl name:%s cur: %lld new: %lld\n", ctrl->name, *ctrl->p_cur.p_s64, *ctrl->p_new.p_s64); v4l2_ctrl_unlock(master); return ret; } As anyone ever used this successfully to read a V4L2_CID_PIXEL_RATE control value? Regards, Benoit -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html