Hi Hans, Thank you for the review. On Wed, Apr 01, 2020 at 04:13:51PM +0200, Hans Verkuil wrote: > On 4/1/20 4:05 PM, 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. > > > > Suggested-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > --- > > Documentation/core-api/printk-formats.rst | 11 +++++++++ > > lib/vsprintf.c | 29 +++++++++++++++++++++++ > > 2 files changed, 40 insertions(+) > > > > diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst > > index 8ebe46b1af39..b6249f513c09 100644 > > --- a/Documentation/core-api/printk-formats.rst > > +++ b/Documentation/core-api/printk-formats.rst > > @@ -545,6 +545,17 @@ For printing netdev_features_t. > > > > Passed by reference. > > > > +V4L2 and DRM fourcc code (pixel format) > > +--------------------------------------- > > + > > +:: > > + > > + %ppf > > + > > +Print a 4cc code used by V4L2 or DRM. > > FourCC appears to be the more-or-less official name (https://en.wikipedia.org/wiki/FourCC) > > I would explain about the -BE suffix for bigendian fourcc variants. Agreed, I'll address these in v2. > > > + > > +Passed by reference. > > + > > Thanks > > ====== > > > > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > > index 7c488a1ce318..b39f0ac317c5 100644 > > --- a/lib/vsprintf.c > > +++ b/lib/vsprintf.c > > @@ -1721,6 +1721,32 @@ char *netdev_bits(char *buf, char *end, const void *addr, > > return special_hex_number(buf, end, num, size); > > } > > > > +static noinline_for_stack > > +char *pixel_format_string(char *buf, char *end, const u32 *fourcc, > > + struct printf_spec spec, const char *fmt) > > +{ > > + char ch[2] = { 0 }; > > This can just be '{ };' As Andy, I also do prefer { 0 }. > > > + unsigned int i; > > + > > + if (check_pointer(&buf, end, fourcc, spec)) > > + return buf; > > + > > + switch (fmt[1]) { > > + case 'f': > > + for (i = 0; i < sizeof(*fourcc); i++) { > > + ch[0] = *fourcc >> (i << 3); > > You need to AND with 0x7f, otherwise a big endian fourcc (bit 31 is set) > will look wrong. Also, each character is standard 7 bit ascii, bit 7 isn't > used except to indicate a BE variant. Good point, will fix for v2. > > > + buf = string(buf, end, ch, spec); > > + } > > + > > + if (*fourcc & BIT(31)) > > + buf = string(buf, end, "-BE", spec); > > + > > + return buf; > > + default: > > + return error_string(buf, end, "(%pp?)", spec); > > + } > > +} > > + > > static noinline_for_stack > > char *address_val(char *buf, char *end, const void *addr, > > struct printf_spec spec, const char *fmt) > > @@ -2131,6 +2157,7 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode, > > * correctness of the format string and va_list arguments. > > * - 'K' For a kernel pointer that should be hidden from unprivileged users > > * - 'NF' For a netdev_features_t > > + * - 'pf' V4L2 or DRM pixel format. > > I'd say 'FourCC format' instead of 'pixel format'. Will fix. -- Regards, Sakari Ailus
