> On 24 Feb 2025, at 9:26 PM, Aditya Garg <gargadity...@live.com> wrote: > > > >> On 24 Feb 2025, at 9:23 PM, andriy.shevche...@linux.intel.com wrote: >> >> On Mon, Feb 24, 2025 at 03:40:29PM +0000, Aditya Garg wrote: >>>>> On 24 Feb 2025, at 9:08 PM, andriy.shevche...@linux.intel.com wrote: >>>> On Mon, Feb 24, 2025 at 03:32:56PM +0000, Aditya Garg wrote: >>>>>> On 24 Feb 2025, at 8:50 PM, Aditya Garg <gargadity...@live.com> wrote: >>>>>>> On 24 Feb 2025, at 8:41 PM, andriy.shevche...@linux.intel.com wrote: >>>>>>> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote: >>>>>>>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevche...@linux.intel.com wrote: >>>>>>>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote: >>>>>>>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevche...@linux.intel.com 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). >>> >>> I still get reverse order in that. >> >> Ah, right, it will give you the first letter as LSB, indeed. At the end of >> the >> day if it's so important, there are ways how to solve that without using >> %p4cc. >> But if others (and esp. PRINTK maintainers) want to have / don't object >> having >> that extension, why not? > > Right, but what to do about the case of little endian and host endian? I > remember the statement "for the sake of completeness" for them. Do you think > just host endian and reverse endian should be just fine? Or you got any "no > sparse warning" way to get it done? The macros to convert to le32/be32 expect > a u32 value, but in those cases we actually are passing a le32/be32 value.
We can convert the __le32 to be printed by %p4cc to __be32. __be32 expected_response_be = cpu_to_be32(le32_to_cpu(expected_response)); That's seems to be the best possible option to fix this revert.
