Messages in this thread |  | | Date | Fri, 3 Apr 2020 12:31:03 +0300 | From | Andy Shevchenko <> | Subject | Re: [PATCH v2 1/1] lib/vsprintf: Add support for printing V4L2 and DRM fourccs |
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On Fri, Apr 03, 2020 at 12:11:56PM +0300, Sakari Ailus wrote: > Add a printk modifier %ppf (for pixel format) for printing V4L2 and DRM > pixel formats denoted by 4ccs. The 4cc encoding is the same for both so > the same implementation can be used.
...
> +static noinline_for_stack > +char *fourcc_string(char *buf, char *end, const u32 *fourcc, > + struct printf_spec spec, const char *fmt) > +{
> +#define FOURCC_STRING_BE "-BE" > + char s[sizeof(*fourcc) + sizeof(FOURCC_STRING_BE)] = { 0 };
I guess it makes it too complicated.
char s[8];
> + if (check_pointer(&buf, end, fourcc, spec)) > + return buf; > + > + if (fmt[1] != 'c' || fmt[2] != 'c') > + return error_string(buf, end, "(%p4?)", spec); > +
> + put_unaligned_le32(*fourcc & ~BIT(31), s);
Can you elaborate what the difference in output with this bit set over cleared? I.o.w. why don't we need to put it as BE and for LE case addd "-LE"?
> + if (*fourcc & BIT(31)) > + strscpy(s + sizeof(*fourcc), FOURCC_STRING_BE, > + sizeof(FOURCC_STRING_BE));
We know the size, and we may put '\0' as well if (*fourcc & BIT(31)) strscpy(&s[4], "-BE", sizeof("-BE")); else strscpy(&s[4], "", sizeof(""));
> + return string(buf, end, s, spec); > +}
-- With Best Regards, Andy Shevchenko
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