linux-kernel - Re: [REGRESSION] 8a3e33cf92c7 "ata: ahci: find eSATA ports and flag them as removable" changes userspace behavior

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Message-ID: <CAOLZvyG4JAdir0F1b2V==qdkM0+NvqxviQeqZ86t=0rbqys7oQ@mail.gmail.com>
Date:	Thu, 25 Feb 2016 20:09:10 +0100
From:	Manuel Lauss <manuel.lauss@...il.com>
To:	Laura Abbott <labbott@...hat.com>
Cc:	Tejun Heo <tj@...nel.org>, Linux-IDE <linux-ide@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [REGRESSION] 8a3e33cf92c7 "ata: ahci: find eSATA ports and flag
 them as removable" changes userspace behavior

On Thu, Feb 25, 2016 at 6:12 PM, Laura Abbott <labbott@...hat.com> wrote:
> Hi,
>
> We received a bugzilla report
> https://bugzilla.redhat.com/show_bug.cgi?id=1310682
> of partitions being automounted unexpectedly. Testing showed that
> 8a3e33cf92c7 ("ata: ahci: find eSATA ports and flag them as removable") was
> responsible.
> This seems to be classified as 'breaking' userspace given that this behavior
> results
> in partitions that were previously unmounted now being being mounted
> unwanted
> automatically which is unwanted behavior for the user. Can we revert this
> patch or
> give a fix to change this behavior?

Can you test this?  I think the old HPCP bit should just be ignored,
although windows does use it, i.e. when I enable hotplug capability
in the bios on my desktop it shows the  "eject device" icon for a device
attached to the port on the motherboard, we probably can ignore it
on linux to not break all automounting distros.  On my laptop, where
I care about this, it still works as intended.

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 4029679..e029e3c 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1164,8 +1164,7 @@ static void ahci_port_init(struct device *dev,
struct ata_port *ap,

        /* mark esata ports */
        tmp = readl(port_mmio + PORT_CMD);
-       if ((tmp & PORT_CMD_HPCP) ||
-           ((tmp & PORT_CMD_ESP) && (hpriv->cap & HOST_CAP_SXS)))
+       if ((tmp & PORT_CMD_ESP) && (hpriv->cap & HOST_CAP_SXS))
                ap->pflags |= ATA_PFLAG_EXTERNAL;
 }