On 06/27/2016 01:57 PM, Nick Dyer wrote: > Hi Hans- > > Thanks for reviewing this again in such detail. > > On 27/06/2016 12:26, Hans Verkuil wrote: >> On 06/23/2016 12:08 AM, Nick Dyer wrote: >>> This is a series of patches to add output of raw touch diagnostic data via V4L2 >>> to the Atmel maXTouch and Synaptics RMI4 drivers. >>> >>> It's a rewrite of the previous implementation which output via debugfs: it now >>> uses a V4L2 device in a similar way to the sur40 driver. >>> >>> We have a utility which can read the data and display it in a useful format: >>> https://github.com/ndyer/heatmap/commits/heatmap-v4l >>> >>> These patches are also available from >>> https://github.com/ndyer/linux/commits/v4l-touch-2016-06-22 >>> >>> Changes in v5 (Hans Verkuil review): >>> - Update v4l2-core: >>> - Add VFL_TYPE_TOUCH, V4L2_BUF_TYPE_TOUCH_CAPTURE and V4L2_CAP_TOUCH >> >> The use of V4L2_CAP_TOUCH and V4L2_BUF_TYPE_TOUCH_CAPTURE is very inconsistent. >> What is the rationale of adding V4L2_BUF_TYPE_TOUCH_CAPTURE? I can't remember >> asking for it. > > I am afraid that I missed updating atmel_mxt_ts from > V4L2_BUF_TYPE_VIDEO_CAPTURE to V4L2_BUF_TYPE_TOUCH_CAPTURE, which has > confused the situation. > > Perhaps I read too much into your request that I look at the way that SDR > is treated. When I started going through the code paths in v4l2-core and > v4l2-compliance, it seemed cleaner to treat touch as completely separate, > hence introducing the new BUF_TYPE. I'm happy to try it without this. Yeah, I didn't mean that you had to add a new BUF_TYPE. My remark was related to ensuring that all occurrences in the spec where they talk about the various /dev/video/radio/etc. devices are extended with v4l-touch as well. > >> And wouldn't the use of V4L2_BUF_TYPE_TOUCH_CAPTURE break userspace for sur40? > > I think it is likely, yes. And it looks like that would make Florian unhappy. > >> I'm ambiguous towards having a V4L2_BUF_TYPE_TOUCH_CAPTURE, to be honest. >> >> I would also recommend renaming V4L2_CAP_TOUCH to V4L2_CAP_TOUCH_CAPTURE. > > Do you agree with the following changes: > > - Rename V4L2_CAP_TOUCH to V4L2_CAP_TOUCH_CAPTURE. > > - Touch devices should register both V4L2_CAP_VIDEO_CAPTURE and > V4L2_CAP_TOUCH_CAPTURE. > > - Get rid of V4L2_BUF_TYPE_TOUCH_CAPTURE and use > V4L2_BUF_TYPE_VIDEO_CAPTURE. In v4l2-ioctl.c if we need to force particular > pix formats for touch, it will need to look at V4L2_CAP_TOUCH_CAPTURE. Actually, I think we have two choices, depending on whether we use a BUF_TYPE_TOUCH_CAPTURE or not. 1) If we go with a BUF_TYPE_TOUCH_CAPTURE, then: - we need a V4L2_CAP_TOUCH_CAPTURE - no V4L2_CAP_VIDEO_CAPTURE will be set (since that would indicate support for BUF_TYPE_VIDEO_CAPTURE, which we don't have anymore). - new callbacks for g/s/try/enum_fmt_tch_cap should be added to v4l2-ioctl.h. 2) Alternatively, if we want to keep using BUF_TYPE_VIDEO_CAPTURE, then: - we keep V4L2_CAP_TOUCH which is combined with CAP_VIDEO_CAPTURE (and perhaps VIDEO_OUTPUT in the future). The CAP_TOUCH just says that this is a touch device, not a video device, but otherwise it acts the same. I'd go with 2, since I see no reason to add a new BUF_TYPE for this. It acts exactly like video after all, with only a few restrictions (i.e. no colorspace info or interlaced). And adding a new BUF_TYPE will likely break the existing sur40 app. > > Your other review comments look straightforward to address - thanks. > > I should say, you can see my current changes to v4l2-compliance here: > https://github.com/ndyer/v4l-utils/commit/07e00c33 > > Should I post them along with the kernel patches next time? Yes, please. Regards, Hans > >> >> I can imagine an embedded usb gadget device that outputs touch data to a PC. >> >> Regards, >> >> Hans > -- > 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
