From patchwork Wed Nov 21 11:50:39 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [v10,10/10] libata: do not suspend port if normal ODD is attached Date: Wed, 21 Nov 2012 01:50:39 -0000 From: Aaron Lu X-Patchwork-Id: 200661 Message-Id: <1353498639-27631-11-git-send-email-aaron.lu@intel.com> To: Jeff Garzik , Tejun Heo , "Rafael J. Wysocki" , Alan Stern Cc: James Bottomley , Jeff Wu , Aaron Lu , linux-ide@vger.kernel.org, linux-linux-pm@vger.kernel.org, linux-acpi@vger.kernel.org For ODDs, the upper layer will poll for media change every a few seconds, which will make it enter and leave suspend state very oftern. And as each suspend will also cause a hard/soft reset, the gain of runtime suspend is very little while the ODD may mis-function after constantly being reset. So the idle callback here will not proceed to suspend if a non-ZPODD capable ODD is attached to the port. Signed-off-by: Aaron Lu --- drivers/ata/libata-core.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 97987e7..9cdfb04 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -5406,8 +5406,27 @@ static int ata_port_resume(struct device *dev) return rc; } +/* + * For ODDs, the upper layer will poll for media change every a few seconds, + * which will make it enter and leave suspend state every a few seconds. And + * as each suspend will cause a hard/soft reset, the gain of runtime suspend + * is very little and the ODD may mis-function after constantly being reset. + * So the idle callback here will not proceed to suspend if a non-ZPODD capable + * ODD is attached to the port. + */ static int ata_port_runtime_idle(struct device *dev) { + struct ata_port *ap = to_ata_port(dev); + struct ata_link *link; + struct ata_device *adev; + + ata_for_each_link(link, ap, HOST_FIRST) { + ata_for_each_dev(adev, link, ENABLED) + if (adev->class == ATA_DEV_ATAPI && + !zpodd_dev_enabled(adev)) + return -EBUSY; + } + return pm_runtime_suspend(dev); }