On 10/15/24 04:01, Warner Losh wrote:
The branch main has been updated by imp:
URL:
https://cgit.FreeBSD.org/src/commit/?id=76bfa33f259891a8b9108e20141bd18e2c8d312f
commit 76bfa33f259891a8b9108e20141bd18e2c8d312f
Author: Warner Losh <i...@freebsd.org>
AuthorDate: 2024-10-15 10:59:29 +0000
Commit: Warner Losh <i...@freebsd.org>
CommitDate: 2024-10-15 10:59:29 +0000
uart: Go back to returning '0' when we've probed the device.
Two reasons for this: we know it's a uart after we call probe and it
returns successfully. Second, uart passes data between probe and attach
with softc. As it is now, we call probe twice, once in the bidding
process and once after bidding id done. However, the probe process for
uart isn't completely idempotent (we change state of the uart
sometimes). The second call can result in odd behavior (though so far
only in buggy version of other code I've not committed). The bigger
problem is the softc: newbus creates it, we populate it, then frees it
when we don't return 0 to claim the device. It then calls us again, we
repopulate it, and this time it doesn't free it before calling attach.
Returning 0 avoids both of these issues. The justification for doing it
in the commit that changed it was 'while I'm here', so there doesn't
seem to be a use case for it.
Hmm, I think it was changed in this commit which wasn't a "while I'm here":
commit b923a71020ae338f723d9aa01b5365c90aae2fec
Author: Marcel Moolenaar <mar...@freebsd.org>
Date: Fri Oct 28 06:30:39 2005 +0000
In uart_bus_probe() return BUS_PROBE_DEFAULT when the probe is
successful.
Notes:
svn path=/head/; revision=151792
diff --git a/sys/dev/uart/uart_core.c b/sys/dev/uart/uart_core.c
index 7b068187e565..b2ff203d0b2a 100644
--- a/sys/dev/uart/uart_core.c
+++ b/sys/dev/uart/uart_core.c
@@ -282,7 +282,7 @@ uart_bus_probe(device_t dev, int regshft, int rclk, int
rid, int chan)
error = UART_PROBE(sc);
bus_release_resource(dev, sc->sc_rtype, sc->sc_rrid, sc->sc_rres);
- return (error);
+ return ((error) ? error : BUS_PROBE_DEFAULT);
}
int
It really is a bug to be depending on passing softc state from probe to
attach and it would be ideal to fix that, but going back to returning 0
is ok for now. Maybe instead of '0' though use BUS_PROBE_SPECIFIC?
--
John Baldwin
