# \[PATCH\] checkpatch: Add test for long udelay - From: Joe Perches \ - Date: 2014-02-04 12:59:32 - List: linux-wireless - Page: https://ratatoskr.run/linux-wireless/2014/02/4191709 - Thread: https://ratatoskr.run/linux-wireless/2014/02/15705814/t.md ```text On Tue, 2014-02-04 at 08:03 +0100, Holger Schurig wrote: > The macro udelay > cannot handle large values because of lost-of-precision. > > IMHO udelay on ARM is broken, because it also cannot work with fast > ARM processors (where bogomips >= 3355, which is in sight now). It's > just not broken enought that someone did something against it ... so > the current kludge is good enought. Until then, warn on long udelay uses. Also fix uses of $line that should have been $herecurr. Signed-off-by: Joe Perches --- scripts/checkpatch.pl | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 0ea2a1e..36275c5 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -3912,10 +3912,15 @@ sub process { # prefer usleep_range over udelay if ($line =~ /\budelay\s*\(\s*(\d+)\s*\)/) { + my $delay = $1; # ignore udelay's < 10, however - if (! ($1 < 10) ) { + if (! ($delay < 10) ) { CHK("USLEEP_RANGE", - "usleep_range is preferred over udelay; see Documentation/timers/timers-howto.txt\n" . $line); + "usleep_range is preferred over udelay; see Documentation/timers/timers-howto.txt\n" . $herecurr); + } + if ($delay > 2000) { + WARN("LONG_UDELAY", + "long udelay - prefer mdelay; see arch/arm/include/asm/delay.h\n" . $herecurr); } } @@ -3923,7 +3928,7 @@ sub process { if ($line =~ /\bmsleep\s*\((\d+)\);/) { if ($1 < 20) { WARN("MSLEEP", - "msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.txt\n" . $line); + "msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.txt\n" . $herecurr); } } ```