PR/57162 CVS commit: [netbsd-10] src/sys

["Martin Husemann" <martin%netbsd.org@localhost>]

The following reply was made to PR kern/57162; it has been noted by GNATS.

From: "Martin Husemann" <martin%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/57162 CVS commit: [netbsd-10] src/sys
Date: Sun, 30 Jul 2023 12:01:54 +0000

 Module Name:	src
 Committed By:	martin
 Date:		Sun Jul 30 12:01:54 UTC 2023
 
 Modified Files:
 	src/sys/arch/amd64/conf [netbsd-10]: ALL
 	src/sys/arch/i386/conf [netbsd-10]: ALL
 	src/sys/dev/acpi [netbsd-10]: acpi_ec.c files.acpi
 
 Log Message:
 Pull up following revision(s) (requested by riastradh in ticket #259):
 
 	sys/dev/acpi/acpi_ec.c: revision 1.102
 	sys/dev/acpi/acpi_ec.c: revision 1.103
 	sys/dev/acpi/acpi_ec.c: revision 1.104
 	sys/dev/acpi/acpi_ec.c: revision 1.105
 	sys/dev/acpi/acpi_ec.c: revision 1.106
 	sys/dev/acpi/acpi_ec.c: revision 1.107
 	sys/dev/acpi/acpi_ec.c: revision 1.108
 	sys/dev/acpi/acpi_ec.c: revision 1.90
 	sys/dev/acpi/acpi_ec.c: revision 1.91
 	sys/dev/acpi/acpi_ec.c: revision 1.92
 	sys/dev/acpi/acpi_ec.c: revision 1.93
 	sys/dev/acpi/acpi_ec.c: revision 1.94
 	sys/dev/acpi/files.acpi: revision 1.128
 	sys/dev/acpi/acpi_ec.c: revision 1.95
 	sys/dev/acpi/acpi_ec.c: revision 1.96
 	sys/dev/acpi/acpi_ec.c: revision 1.97
 	sys/arch/amd64/conf/ALL: revision 1.179
 	sys/dev/acpi/acpi_ec.c: revision 1.98
 	sys/dev/acpi/acpi_ec.c: revision 1.99
 	sys/dev/acpi/acpi_ec.c: revision 1.87
 	sys/dev/acpi/acpi_ec.c: revision 1.88
 	sys/dev/acpi/acpi_ec.c: revision 1.89
 	sys/arch/i386/conf/ALL: revision 1.511
 	sys/dev/acpi/acpi_ec.c: revision 1.100
 	sys/dev/acpi/acpi_ec.c: revision 1.101
 
 acpiec(4): Record device_t self.
 
 Not used yet, to be used soon for device_printf and to allow making
 some of the internal functions a little more type-safe later.
 acpiec(4): New ACPIEC_DEBUG option.
 
 Value is bit mask of debug messages to enable.
 
 Enable in x86/ALL kernels.
 
 No functional change intended when the option is off.
 
 acpiec(4): Clarify lock order and sprinkle lock assertions.
 No functional change intended.
 
 acpiec(4): Sprinkle comments.
 Note where this code is abusing cv_wait and needs a loop to handle
 spurious wakeups.
 No functional change intended.
 
 acpiec(4): Assert state is free when we start a transaction.
 No functional change intended.
 
 acpiec(4): Set sc_got_sci only when a transaction is over.
 
 Before, when the acpiec thread noticed an SCI had been requested and
 entered acpiec_gpe_state_machine to send the query command, it would
 see the SCI is still requested -- because it had yet to acknowledge
 it by setting the query command! -- and think the EC was asking for a
 _second_ SCI.
 
 So once the first SCI transaction was over, it would start a second
 one, even though the EC hadn't asked for another -- and this would
 wedge on some ECs.
 
 Now, acpiec_gpe_state_machine waits to see what state we transition
 to before taking the SCI bit to mean we need to notify the acpiec
 thread to handle another query.
 
 That way, when the acpiec thread enters acpiec_gpe_state_machine with
 EC_STATE_QUERY, it can send the query command first, with the side
 effect of clearing the SCI bit in subsequent reads of the status
 register, and it won't think another SCI has been requested until it
 returns to EC_STATE_FREE and sees the SCI bit set again in the status
 register.
 
 Possibly relevant PRs:
 PR kern/53135
 PR kern/52763
 PR kern/57162
 
 acpiec(4): Fix cv_wait loop around sc->sc_got_sci.
 
 That is, make it actually loop as required, so it gracefully handles
 spurious wakeups instead of barging into invalid states.
 
 acpiec(4): Fix interrupt wait loop in acpiec_gpe_query thread.
 
 acpiec(4): Fix cv_timedwait abuse in acpiec_read/write.
 
 acpiec(4): Don't touch sc->sc_state outside sc->sc_mtx.
 
 acpiec(4): Merge returns in acpiec_read/write.
 No functional change intended.
 
 acpiec(4): Factor wait logic out.
 No functional change intended.
 
 acpiec(4): Pass softc, not device_t, to acpiec_gpe_state_machine.
 Simpler, type-safer.
 No functional change intended.
 
 acpiec(4): Pass softc, not device_t, to acpiec_callout.
 Simpler.
 No functional change intended.
 
 acpiec(4): Pass softc, not device_t, to acpiec_gpe_handler.
 Simpler.
 No functional change intended.
 
 acpiec(4): Pass softc, not device_t, to acpiec_lock/unlock.
 Simpler, type-safer.
 No functional change intended.
 
 acpiec(4): Pass softc, not device_t, to acpiec_read/write.
 Simpler, type-safer.
 No functional change intended.
 
 acpiec(4): Pass softc, not device_t, to acpiec_gpe_query thread.
 Simpler.
 No functional change intended.
 
 acpiec(4): Pass softc, not device_t, to acpiec_space_handler.
 Better to keep the device_t isolated to public interfaces.  Simpler
 internally this way.
 No functional change intended.
 
 acpiec(4): Factor out if (state == FREE) cv_signal(sc_cv).
 
 In principle this could have a functional change, but at worst, it is
 to signal more wakeups than needed, which should always be safe.
 acpiec(4): Take a lock around acpiec_cold updates.
 
 Otherwise we race with readers -- probably harmlessly, but let's
 avoid the appearance of problems.
 XXX Maybe acpiec_suspend and acpiec_shutdown should interrupt
 transactions and force them to fail promptly?
 XXX This looks bad because acpiec_cold is global and sc->sc_mtx
 doesn't look like it's global, but we expect to have only one
 acpiec(4) device anyway from what I understand.  Maybe we should move
 acpiec_cold into the softc?
 
 acpiec(4): One more debug message about read/write polling timeout.
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.174 -r1.174.4.1 src/sys/arch/amd64/conf/ALL
 cvs rdiff -u -r1.503 -r1.503.4.1 src/sys/arch/i386/conf/ALL
 cvs rdiff -u -r1.86 -r1.86.4.1 src/sys/dev/acpi/acpi_ec.c
 cvs rdiff -u -r1.126 -r1.126.4.1 src/sys/dev/acpi/files.acpi
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.