Hi Wolfram, On 15/04/2020 09:16, Wolfram Sang wrote: > >> Aha, is it easy enough to distinguish that difference in user-space so >> that we can present a specific character to indicate this in i2cdetect? >> Or is that not so easy? > > I thought about it shortly but have not come up with a way of doing > that. This is the code in i2cdetect: > > /* Set slave address */ > if (ioctl(file, I2C_SLAVE, i+j) < 0) { > if (errno == EBUSY) { > printf("UU "); > continue; > } else { > fprintf(stderr, "Error: Could not set " > "address to 0x%02x: %s\n", i+j, > strerror(errno)); > return -1; > } > } > > So, if we chose to use another errno to indicate 'reserved' and update > i2cdetect, all old versions of i2cdetect will have ugly error messages. > And adding another IOCTL just for printing reserved addresses neither > sounds great. Indeed, a different errno would be about all we could do - and it would seemingly leave old i2cdetects with complete failures, if it goes through that non-EBUSY code path. Ayeeeee :-S -- Kieran