From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Sergey Zakharchenko <doublef.mobile@gmail.com>
Cc: Sergey Zakharchenko <szakharchenko@digital-loggers.com>,
linux-media@vger.kernel.org,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Martin Bodo <martin@digital-loggers.com>,
"Logan, Peter" <peter.logan@intel.com>,
Auke Kok <auke-jan.h.kok@intel.com>
Subject: Re: [PATCH v2] media: uvcvideo: Add a quirk to force GEO GC6500 Camera bits-per-pixel value
Date: Wed, 2 Oct 2019 22:08:05 +0300 [thread overview]
Message-ID: <20191002190805.GG5262@pendragon.ideasonboard.com> (raw)
In-Reply-To: <CADYCxoNTBmX8RYf18xmX0B8xD_LvNJbZ5buyAgo5E9v14B3S_A@mail.gmail.com>
Hi Sergey,
On Wed, Oct 02, 2019 at 09:15:45PM +0400, Sergey Zakharchenko wrote:
> Sergey Zakharchenko <doublef.mobile@gmail.com>:
> > Laurent Pinchart <laurent.pinchart@ideasonboard.com>:
> > > Do you think it would make sense to do this by default, without
> > > requiring a quirk ? Or are there cases where this calculation would lead
> > > to incorrect results while the bpp reported by the camera would be right
> > > ?
> >
> > The loop is a simplified version of the v4l2_fill_pixfmt() loop. The
> > calculation might need some checking, and might be invalid, in case
> > block_w/block_h format fields are significant (not 0 and not 1),
> > because then effective bits-per-pixel would seemingly be fractional,
> > and depend on the image dimensions if they weren't aligned; however I
> > see no formats using the block_w/block_h fields defined so far.
>
> It's likely possible to directly replace the bpp-using computation in
> https://github.com/torvalds/linux/blob/2874c5fd284268364ece81a7bd936f3c8168e567/drivers/media/usb/uvc/uvc_driver.c#L636
> with a call to v4l2_fill_pixfmt() and the sizeimage it returns.
> However, bpp is used elsewhere, and it's hard to tell what it should
> be taken to be to in the hypothetical exotic cases I'm considering, so
> I'm reluctant to go that route.
Would it make sense to split the calculation from v4l2_fill_pixfmt() to
a helper function that the UVC driver could call ?
> I'm going to send v3 in an hour unless there are other suggestions.
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2019-10-02 19:09 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-02 8:47 [PATCH] media: uvcvideo: Add a quirk to force GEO GC6500 Camera bits-per-pixel value Sergey Zakharchenko
2019-10-02 12:00 ` kbuild test robot
2019-10-02 13:01 ` [PATCH v2] " Sergey Zakharchenko
2019-10-02 14:08 ` Laurent Pinchart
2019-10-02 14:54 ` Sergey Zakharchenko
2019-10-02 17:15 ` Sergey Zakharchenko
2019-10-02 19:08 ` Laurent Pinchart [this message]
2019-10-02 19:29 ` Sergey Zakharchenko
2019-10-03 9:31 ` [PATCH v3] " Sergey Zakharchenko
2019-12-18 18:00 ` Laurent Pinchart
2019-12-18 18:46 ` Sergey Zakharchenko
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