From 09196af60d0e7dc8b06ac78e5998d29bde66b065 Mon Sep 17 00:00:00 2001 From: Damien Lespiau Date: Mon, 7 Jul 2014 15:16:51 +0100 Subject: [PATCH] pipe_crc: Warn if the CRC values is 0xffffffff This is what we read when the CRC logic in in a powered down well. We really don't want that to happen. In theory, it's possible 0xffffffff to be a valid CRC value, so I don't assert here. Signed-off-by: Damien Lespiau --- lib/igt_debugfs.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/lib/igt_debugfs.c b/lib/igt_debugfs.c index 2f655a1d..5c4bbc59 100644 --- a/lib/igt_debugfs.c +++ b/lib/igt_debugfs.c @@ -199,9 +199,14 @@ bool igt_crc_is_null(igt_crc_t *crc) { int i; - for (i = 0; i < crc->n_words; i++) + for (i = 0; i < crc->n_words; i++) { + if (crc->crc[i] == 0xffffffff) + igt_warn("Suspicious CRC: it looks like the CRC " + "read back was from a register in a powered " + "down well\n"); if (crc->crc[i]) return false; + } return true; }