Fix RMT buffer allocation #3512
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Merge upstream
With the >= used let's say you have four RMT inputs, each using 2 channels wide for their receive buffer. This is 4*2 = 8 buffers which is the number of hardware buffers (MAX_CHANNELS). But, for the fourth input the starting buffer will be 6 (this is correct, the buffers used for each input are 0-1, 2-3, 4-5, 6-7). But, 6+2 = 8 which is MAX_CHANNELS. This is valid but the >= would match against it and abort. It is correct to only abort if the value i+j is only greater than MAX_CHANNELS. Thus, a simple one character fix. Delete the equals sign.
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nice find :) just love those type of bugs |
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As the code sits, you can't use the last RMT buffer, basically because of an off by one style error. The comparison I changed should be "greater than" only not "greater than or equal to." It's OK if i+j = MAX_CHANNELS. In the case of having four inputs, all using 2 buffers each, this leads to i being 0, 2, 4, 6 and each takes up two buffers so the allocation is 0-1, 2-3, 4-5, 6-7. The 6-7 is the problem because i+j will equal 8 but really that still means only 6-7 are being used as j is always one larger than the actual offset from the starting buffer.