On Mon, Feb 24, 2025 at 03:32:56PM +0000, Aditya Garg wrote: > > On 24 Feb 2025, at 8:50 PM, Aditya Garg <gargaditya08@xxxxxxxx> wrote: > >> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@xxxxxxxxxxxxxxx wrote: > >> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote: > >>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@xxxxxxxxxxxxxxx wrote: > >>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote: > >>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@xxxxxxxxxxxxxxx wrote: > >>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote: ... > >>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3])) > >>>>>>> > >>>>>>> As commented previously this is quite strange what's going on with endianess in > >>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being > >>>>>>> open coded and force-cast to __le32. > >>>>>> > >>>>>> I would assume it was also mimicked from the Windows driver, though I haven't > >>>>>> really tried exploring this there. > >>>>>> > >>>>>> I’d rather be happy if you give me code change suggestions and let me review > >>>>>> and test them > >>>>> > >>>>> For the starter I would do the following for all related constants and > >>>>> drop that weird and ugly macros at the top (it also has an issue with > >>>>> the str4 length as it is 5 bytes long, not 4, btw): > >>>>> > >>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */ > >>> > >>> Lemme test this. > >> > >> Just in case it won't work, reverse bytes in the integer. Because I was lost in > >> this conversion. > > > > It works. What I understand is that you used the macro to get the final hex and converted it into little endian, which on the x86 macs would technically remain the same. > > And now that I oberved again, %p4cc is actually printing these CLRD, REDY etc > in reverse order, probably the reason %p4ch was chosen. And I am unable to > find what macro upstream can be used. %.4s should work as it technically not DRM 4cc, but specifics of the protocol (that reminds me about ACPI that uses 4cc a lot). -- With Best Regards, Andy Shevchenko
