git: 9be96a2158bb - stable/14 - acpi/apm: Improve APM ioctl interface emulation

The branch stable/14 has been updated by imp:

URL: https://cgit.FreeBSD.org/src/commit/?id=9be96a2158bbaa1af65ef88b1f4e9c57ec5296e4

commit 9be96a2158bbaa1af65ef88b1f4e9c57ec5296e4
Author:     Warner Losh <imp@FreeBSD.org>
AuthorDate: 2024-01-03 23:18:23 +0000
Commit:     Warner Losh <imp@FreeBSD.org>
CommitDate: 2024-12-28 18:11:09 +0000

    acpi/apm: Improve APM ioctl interface emulation
    
    The apm(8) program documents certain states, but doesn't document the
    'unknown' state. It reports things correctly for systems with a battery,
    but incorrectly for systems without one. Emulate the old interface a
    little better by saying ac power is online if we have no status (instead
    of unknown), the battery has a high charge of 255% if there's no battery
    (instead of -1). Programs, like emacs, expect to see only the documented
    values and misbehave when they see something else.
    
    This is closer to what would happen on old-school APM machines. Sadly
    (or not) I have no access to old-school APM machines to 100% confirm
    this, but reading the spec, old code and testing with emacs' mode line
    with battery suggests these values are more correct. emacs has never
    been converted to acpi_conf due to permissions issues with acpi devices.
    
    Fixing the kernel is preferable to hacking apm(8) for these special
    cases because other programs that use these interfaces will also be more
    correct. The kernel also has more data with which to decide what to
    return.
    
    Sponsored by:   Netflix
    MFC After:      1 week
    
    (cherry picked from commit 8a3fafc821149e800747cd92afee092fd131c402)
---
 sys/x86/acpica/acpi_apm.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/sys/x86/acpica/acpi_apm.c b/sys/x86/acpica/acpi_apm.c
index e7e4b0f1a546..b602047d7bca 100644
--- a/sys/x86/acpica/acpi_apm.c
+++ b/sys/x86/acpica/acpi_apm.c
@@ -142,18 +142,18 @@ acpi_capm_get_info(apm_info_t aip)
 	aip->ai_capabilities= 0xff00;	/* unknown */
 
 	if (acpi_acad_get_acline(&acline))
-		aip->ai_acline = APM_UNKNOWN;	/* unknown */
+		aip->ai_acline = 1;		/* no info -- on-line best guess */
 	else
 		aip->ai_acline = acline;	/* on/off */
 
 	if (acpi_battery_get_battinfo(NULL, &batt) != 0) {
-		aip->ai_batt_stat = APM_UNKNOWN;
-		aip->ai_batt_life = APM_UNKNOWN;
-		aip->ai_batt_time = -1;		 /* unknown */
-		aip->ai_batteries = ~0U;	 /* unknown */
+		aip->ai_batt_stat = 0;		/* "high" old I/F has no unknown state */
+		aip->ai_batt_life = 255;	/* N/A, not -1 */
+		aip->ai_batt_time = -1;		/* unknown */
+		aip->ai_batteries = ~0U;	/* unknown */
 	} else {
 		aip->ai_batt_stat = acpi_capm_convert_battstate(&batt);
-		aip->ai_batt_life = batt.cap;
+		aip->ai_batt_life = (batt.cap == -1) ? 255 : batt.cap;
 		aip->ai_batt_time = (batt.min == -1) ? -1 : batt.min * 60;
 		aip->ai_batteries = acpi_battery_get_units();
 	}
@@ -187,11 +187,11 @@ acpi_capm_get_pwstatus(apm_pwstatus_t app)
 
 	app->ap_batt_stat = acpi_capm_convert_battstate(&batt);
 	app->ap_batt_flag = acpi_capm_convert_battflags(&batt);
-	app->ap_batt_life = batt.cap;
+	app->ap_batt_life = (batt.cap == -1) ? 255 : batt.cap;
 	app->ap_batt_time = (batt.min == -1) ? -1 : batt.min * 60;
 
 	if (acpi_acad_get_acline(&acline))
-		app->ap_acline = APM_UNKNOWN;
+		app->ap_acline = 1;		/* no info -- on-line best guess */
 	else
 		app->ap_acline = acline;	/* on/off */