Fix inability to use all buffers in RMT (#3512)

collin80 · me-no-dev · commit 7b3c1dfd508a · 2020-01-20T15:31:44.000+02:00
With the &gt;= 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 &gt;= 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.
diff --git a/cores/esp32/esp32-hal-rmt.c b/cores/esp32/esp32-hal-rmt.c
@@ -483,7 +483,7 @@ rmt_obj_t* rmtInit(int pin, bool tx_not_rx, rmt_reserve_memsize_t memsize)
             break;
         }
     }
-    if (i == MAX_CHANNELS || i+j >= MAX_CHANNELS || j != buffers)  {
+    if (i == MAX_CHANNELS || i+j > MAX_CHANNELS || j != buffers)  {
         xSemaphoreGive(g_rmt_block_lock);
         return NULL;
     }

Original file line number	Diff line number	Diff line change
`@@ -483,7 +483,7 @@ rmt_obj_t* rmtInit(int pin, bool tx_not_rx, rmt_reserve_memsize_t memsize)`
`483`	`483`	`break;`
`484`	`484`	`}`
`485`	`485`	`}`
`486`		`- if (i == MAX_CHANNELS \|\| i+j >= MAX_CHANNELS \|\| j != buffers) {`
	`486`	`+ if (i == MAX_CHANNELS \|\| i+j > MAX_CHANNELS \|\| j != buffers) {`
`487`	`487`	`xSemaphoreGive(g_rmt_block_lock);`
`488`	`488`	`return NULL;`
`489`	`489`	`}`