> On 24 Feb 2025, at 3:28 PM, andriy.shevchenko@xxxxxxxxxxxxxxx wrote: > > On Sat, Feb 22, 2025 at 03:46:03PM +0000, Aditya Garg wrote: >>>> On 20 Feb 2025, at 10:09 PM, Aditya Garg <gargaditya08@xxxxxxxx> wrote: >>> >>> %p4cc is designed for DRM/V4L2 FOURCCs with their specific quirks, but >>> it's useful to be able to print generic 4-character codes formatted as >>> an integer. Extend it to add format specifiers for printing generic >>> 32-bit FOURCCs with various endian semantics: >>> >>> %p4ch Host-endian >>> %p4cl Little-endian >>> %p4cb Big-endian >>> %p4cr Reverse-endian >>> >>> The endianness determines how bytes are interpreted as a u32, and the >>> FOURCC is then always printed MSByte-first (this is the opposite of >>> V4L/DRM FOURCCs). This covers most practical cases, e.g. %p4cr would >>> allow printing LSByte-first FOURCCs stored in host endian order >>> (other than the hex form being in character order, not the integer >>> value). > > ... > >> BTW, after looking at the comments by Martin [1], its actually better to use >> existing specifiers for the appletbdrm driver. The driver needs the host >> endian as proposed by this patch, so instead of that, we can use %.4s > > Do you mean this patch will not be needed? If this a case, that would be the > best solution. I tested with %4pE, and the results are different from expected. So this would be preferred. Kindly see my latest email with a proposed workaround for the sparse warnings. > >> [1]: https://lore.kernel.org/asahi/E753B391-D2CB-4213-AF82-678ADD5A7644@xxxxxxxxxxx/ >> >> Alternatively we could add a host endian only. Other endians are not really >> used by any driver AFAIK. The host endian is being used by appletbdrm and >> Asahi Linux’ SMC driver only. > > -- > With Best Regards, > Andy Shevchenko > >
