apause.exp: catch and print error messages and exit immediately

Fail fast and avoid timeouts.

This is especially important considering pause will soon be disabled by
default:
- thesofproject/linux#5041

Signed-off-by: Marc Herbert <[email protected]>

case-lib/apause.exp

@@ -137,8 +137,20 @@ set volume_always_zero true
 
 expect {
 
+ # `man re_syntax` claims that Tcl regular expressions are compliant
+ # with the basic and extended POSIX ones while adding a 3rd,
+ # extended flavor. It's not clear which flavor `expect -re` uses
+ # but it's not the basic one.
+ # Use {} not "" to avoid quoting issues and backslash proliferation.
+
  # When multiple patterns match, first pattern wins.
 
+ -nocase -re {error.*\r|PAUSE.*no[[:blank:]]*hw[[:blank:]]*support.*\r} {
+ set buffer_with_lf "[cr_to_lf $expect_out(buffer)]"
+ log 0 "ERROR: $buffer_with_lf"
+ exit 1
+ }
+
  # Volume xx% or MAX line
  #
  # When not backpressured by a sleeping (=bad!) Expect process,