Only attempt to set default sample count if supported.

diff --git a/pv/toolbars/samplingbar.cpp b/pv/toolbars/samplingbar.cpp
index 6109c163ef4b11ecd6d8fdcc873618e44dc17a66..987719d8c2f45cfa37db50a03b95c7e34bcbf70d 100644 (file)
--- a/pv/toolbars/samplingbar.cpp
+++ b/pv/toolbars/samplingbar.cpp
@@ -54,6 +54,7 @@ SamplingBar::SamplingBar(SigSession &session, QWidget *parent) :
        _sample_rate("Hz", this),
        _updating_sample_rate(false),
        _updating_sample_count(false),
+       _sample_count_supported(false),
        _icon_red(":/icons/status-red.svg"),
        _icon_green(":/icons/status-green.svg"),
        _icon_grey(":/icons/status-grey.svg"),
@@ -210,10 +211,12 @@ void SamplingBar::update_sample_count_selector()
        if (sr_config_get(sdi->driver, sdi, NULL,
                SR_CONF_LIMIT_SAMPLES, &gvar) != SR_OK)
        {
+               _sample_count_supported = false;
                _sample_count.show_none();
        }
        else
        {
+               _sample_count_supported = true;
                _sample_count.show_min_max_step(0, UINT64_MAX, 1);
 
                samplecount = g_variant_get_uint64(gvar);
@@ -285,7 +288,7 @@ void SamplingBar::on_device_selected()
        update_sample_count_selector();
        update_sample_rate_selector();
 
-       if (_sample_count.value() == 0) {
+       if (_sample_count_supported && _sample_count.value() == 0) {
                _sample_count.set_value(DefaultRecordLength);
                commit_sample_count();
        }

diff --git a/pv/toolbars/samplingbar.h b/pv/toolbars/samplingbar.h
index 41630bcab92703d7a7ff44a1ae02c47192c912db..db4c10e48fa4065221cb3004c250a00abc1a222f 100644 (file)
--- a/pv/toolbars/samplingbar.h
+++ b/pv/toolbars/samplingbar.h
@@ -92,6 +92,8 @@ private:
        bool _updating_sample_rate;
        bool _updating_sample_count;
 
+       bool _sample_count_supported;
+
        QIcon _icon_red;
        QIcon _icon_green;
        QIcon _icon_grey;