Messages in this thread | | | Subject | Re: [RFC/BUG?] ide_cs's removable status | From | Alan Cox <> | Date | Wed, 21 Sep 2005 17:57:08 +0100 |
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On Mer, 2005-09-21 at 17:15 +0100, Richard Purdie wrote: > As ide_cs only creates the block devices when a card is present, I think > it shouldn't be set as removable. As a point of reference, the MMC > system does not set the removable flag for exactly this reason (There is > an email from Russell King explaining this - > http://lkml.org/lkml/2005/1/8/165).
I can't comment on the MMC layer or its core requirements as I don't know them well. IDE PCMCIA does however encompass removal devices. The removable flag is set so that we get removable media behaviour - that is the media can change under us and we must not cache partition data. The current behavioiur in that sense is correct.
> > It is worth noting the MMC subsystem works with my evil udev script. If > I apply the patch below (which removes the removable flag for flash > devices), I don't see this loop.
But does MMC have a media change detect, and if not does the right thing occur if you swap cards with partition tables ?
> 1. Can anyone provide details on what the bits in id->config really > mean?
ATA standards are all available for download.
> 2. Which other drivers exploit the "if (id->config & (1<<7)) > drive->removable = 1;" code? Is it just ide_cs?
It might be currently because the old IDE layer has no hotplug support (not even for PCMCIA - it happens to work some days) but that wasn't true in 2.4-ac or some 2.6-ac.
It sounds like something needs to be smarter about whether the media has changed - could be kernel but it seems like a user space problem. I note that the standard Gnome tools "just work" in this case so perhaps you can see how they do it.
Alan
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