On Wed, 18 Nov 2015 16:14:43 +0100, Lin, Mengdong wrote: > > > -----Original Message----- > > From: Takashi Iwai [mailto:tiwai@xxxxxxx] > > Sent: Wednesday, November 18, 2015 4:19 PM > > > > On Wed, 18 Nov 2015 08:28:09 +0100, > > Lin, Mengdong wrote: > > > > > > > -----Original Message----- > > > > From: Takashi Iwai [mailto:tiwai@xxxxxxx] > > > > Sent: Wednesday, November 18, 2015 3:16 PM > > > > To: mengdong.lin@xxxxxxxxxxxxxxx > > > > > > > On Wed, 18 Nov 2015 08:23:07 +0100, > > > > mengdong.lin@xxxxxxxxxxxxxxx wrote: > > > > > > > > > > From: Mengdong Lin <mengdong.lin@xxxxxxxxxxxxxxx> > > > > > > > > > > Fix warning: comparison between signed and unsigned integer > > > > > expressions [-Wsign-compare] > > > > > > > > > > ABI objects use type _le32, which is converted to host unsigned integer. > > > > > So the iterator 'i' in a loop as below should also be unsigned. > > > > > for (i = 0; i < pcm->num_streams; i++) > > > > > ^ > > > > > > > > Using an unsigned int for the generic loop count like i is strange. > > > > > > Yes. > > > > > > > Rather compare with the original value in the template, which is actually int. > > > > > > Are you suggesting not change the code? > > > > No. > > > > > The "pcm->num_streams" here is __le32 defined in ABI: > > > struct snd_soc_tplg_pcm { > > > ... > > > __le32 num_streams; /* number of streams */ > > > ... > > > } __attribute__((packed)); > > > > > > It seems gcc takes it as unsigned integer and so I get the warning. > > > > The problem isn't only about the endianess. > > Conceptually, it's wrong to refer directly to le32 data, as it's not being CPU > > endian. It should have always an endian conversion. Of course, we support > > only LE32, so it's no big issue, so far. > > > > What you need to refer to is the value in the template instead. It's guaranteed > > to be CPU endianess, and it's even int. > > So, the code would look like: > > > > for (i = 0; i < pcm_tpl->num_streams; i++) > > > Okay, I'll revise the patch. Thanks for your suggestion. > > > BTW, I haven't checked whether topology API would "work" on big-endian > > architecture; does it return an error properly? > > Sorry, no. I'll check if an API can tell us the host endianness and let topology return an error for big-endian machines. > > I had thought to use this API when generating the ABI objects from host type to _le32: > uint32_t htole32(uint32_t host_32bits); Yes, that should work. But then, as I pointed out, many current codes directly refer to the converted data, and they are broken. > But since I have no big-endian machines to test this, maybe it's better to return an error for them. It's the easiest option, of course :) Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
