On 11/16/2011 07:27 PM, Dmitry Torokhov wrote:
Hi Nuno, On Wed, Nov 16, 2011 at 05:28:13PM +0000, Nuno Santos wrote:Why? I thought this thing is an input device? Why does an application have to modify a running device? Is this modification local to the application<->device interface or does it also affect all other running applications that use this device? If it is a configuration value to put the device into a different state or similar, then you can use a sysfs attribute. The user can change this with "echo<value> >/sys/class/input/inputX/<attribute>"Any chance you could use some sane quoting style? It is almost impossible to dechipher where someone else's mail stops and your reply starts.
Yes, sorry.
I'm already with working examples of ATTRIB in my driver project. The thing is that I have random kernel panics when I try to read from the attribute. This is my attribute code: static ssize_t usbtouchscreen_get_state(struct device *dev, struct device_attribute *attr, char *buf) { int count=0; struct usbtouch_usb *usbtouch = dev_get_drvdata(dev); struct dpx_priv *priv = usbtouch->priv; printk(KERN_INFO "state length: %d",sizeof(DPX_DEVICE_STATE)); // size = 43196 bytesSo it is probably 39K more than sysfs attribute can handle.
Ok, I found on documentation that buffer size is maximum PAGE_SIZE
Now that i'm copying the proper amount of data I have another problem. I'm actually reading this attribute constantly when I open my control panel, however it seems that I can only have reading results from second to second. Is there anything that limits the amount of times I can push attribute data per second? I would definitily need at least 40 readings per second in order to have my data visualized in control panel.memcpy(buf,(void*)&priv->context->State,sizeof(DPX_DEVICE_STATE));and you are smashing kernel stack here.
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