Hi Devin, On 09/22/2014 01:21 PM, Devin Heitmueller wrote: > Hi Shuah, > > What about G_INPUT and G_TUNER? Consider the following use case, which is > entirely legal in the V4L2 API: Did you mean G_INPUT and G_STD here? I didn't see G_TUNER mentioned below in the use-case. I didn't know this use-case, I did notice ENUM_INPUT getting called in a loop during testing. I think I didn't run into this because I changed the au0828: vidioc_g_tuner to hold the lock as it does a tuner init and messes up the tuner when it is in use by dvb. But, that doesn't cover this use-case for other drivers. So I need to make more changes to cover it. Thanks for pointing this out. > > 1. Program opens /dev/video0 > 2. Program calls G_INPUT/G_STD and sees that the appropriate input and > standard are already set, since all devices have a default input at > initialization > 3. Program never calls S_INPUT, S_STD, or S_TUNER > 4. Program goes into a loop calling ENUM_INPUT, waiting until it returns > the input as having signal lock > 5. When signal lock is seen, program calls STREAMON. I am missing vb2 streamon change to hold the tuner in this patch set. Without that change vb2 work isn't complete. Unfortunately I don't have hybrid hardware that uses a vb2 driver. > > In the above case, you would be actively using the au8522 video decoder but > not holding the lock, so thr DVB device can be opened and screw everything > up. Likewise if the DVB device were in use and such a program were run, it > wouls break. > I think this use-case will be covered with changes to vb2 streamon to check and hold tuner. I am thinking it might not be necessary to change g_tuner, g_std, g_input and enum_input at v4l2-core level. Does that sounds right?? thanks, -- Shuah -- Shuah Khan Sr. Linux Kernel Developer Samsung Research America (Silicon Valley) shuahkh@xxxxxxxxxxxxxxx | (970) 217-8978 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
