Matthew Garrett wrote:
Modern laptops with hotswap bays still tend to utilise a PATA interface
on a SATA bridge, generally with the host controller in some legacy
emulation mode rather than AHCI. This means that the existing hotplug
code in libata is unable to work. The ACPI specification states that
these devices can send notifications when hotswapped, which avoids the
need to obtain notification from the controller. This patch uses the
existing libata-acpi code and simply registers a notification in order
to trigger a rescan whenever the firmware signals an event.
Signed-off-by: Matthew Garrett <mjg59@xxxxxxxxxxxxx>
---
This makes two changes to the previous patch:
1) It implements the locking suggested by Tejun
2) It sends a uevent on the device kobject. I've implemented this
because grabbing the notification handler means that the bay driver can
no longer do it, so it's necessary to generate compatible events. If the
event type is 3, it indicates that the user has merely requested an
eject - the drive hasn't gone at this point. Sending the notification
allows userspace to attempt to unmount the filesystems before sending a
command to initiate the eject.
I'm not especially happy about the chain used to get the scsi device
kobject. Is there a cleaner way to do that? Other than that, I've now
tested this on multiple systems (a 965-based Thinkpad, a 915-era Dell
and even an HP with no SATA whatsoever) without any obvious breakage.
diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
index c059f78..68bb7fa 100644
--- a/drivers/ata/libata-acpi.c
+++ b/drivers/ata/libata-acpi.c
@@ -14,6 +14,7 @@
#include <linux/acpi.h>
#include <linux/libata.h>
#include <linux/pci.h>
+#include <scsi/scsi_device.h>
#include "libata.h"
#include <acpi/acpi_bus.h>
@@ -66,6 +67,41 @@ static void ata_acpi_associate_ide_port(struct ata_port *ap)
}
}
+static void ata_acpi_notify(acpi_handle handle, u32 event, void *data)
+{
+ struct ata_port *ap = data;
+ struct ata_eh_info *ehi = &ap->eh_info;
+ char event_string[12];
+ char *envp[] = { event_string, NULL };
+ struct kobject *kobj = NULL;
+ int i;
+
+ if (ap->acpi_handle && handle == ap->acpi_handle)
+ kobj = &ap->dev->kobj;
+ else {
+ for (i = 0; i < ata_port_max_devices(ap); i++) {
+ struct ata_device *dev = &ap->device[i];
+ if (dev->acpi_handle && handle == dev->acpi_handle)
+ kobj = &dev->sdev->sdev_gendev.kobj;
+ }
+ }
+
+ if (event == 0 || event == 1) {
+ unsigned long flags;
+ spin_lock_irqsave(ap->lock, flags);
+ ata_ehi_clear_desc(ehi);
+ ata_ehi_push_desc(ehi, "ACPI event");
+ ata_ehi_hotplugged(ehi);
+ ata_port_freeze(ap);
+ spin_unlock_irqrestore(ap->lock, flags);
+ }
+
+ if (kobj) {
+ sprintf(event_string, "BAY_EVENT=%d\n", event);
+ kobject_uevent_env(kobj, KOBJ_CHANGE, envp);
+ }
+}
+
/**
* ata_acpi_associate - associate ATA host with ACPI objects
* @host: target ATA host
@@ -81,7 +117,7 @@ static void ata_acpi_associate_ide_port(struct ata_port *ap)
*/
void ata_acpi_associate(struct ata_host *host)
{
- int i;
+ int i, j;
if (!is_pci_dev(host->dev) || libata_noacpi)
return;
@@ -97,6 +133,22 @@ void ata_acpi_associate(struct ata_host *host)
ata_acpi_associate_sata_port(ap);
else
ata_acpi_associate_ide_port(ap);
+
+ if (ap->acpi_handle)
+ acpi_install_notify_handler (ap->acpi_handle,
+ ACPI_SYSTEM_NOTIFY,
+ ata_acpi_notify,
+ ap);
+
+ for (j = 0; j < ata_port_max_devices(ap); j++) {
+ struct ata_device *dev = &ap->device[j];
+
+ if (dev->acpi_handle)
+ acpi_install_notify_handler (dev->acpi_handle,
+ ACPI_SYSTEM_NOTIFY,
+ ata_acpi_notify,
+ ap);
Mostly OK. Notes:
1) Check dev->sdev for NULL
2) remove the unnecessary ata_device loop. If you know the ata_device
pointer, you should not throw it away and then do a search to find it again.
You need two functions, ata_acpi_ap_notify() and ata_acpi_dev_notify().
Pass 'ap' to the former, and 'dev' to the latter.
Both functions should marshal their arguments, then call a common
function (presumably what 95% of current ata_acpi_notify does).
3) Won't this result in a single hotplug event calling
ata_ehi_hotplugged() multiple times -- once for the port, and once for
each device attached to the port?
-
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