On Jun 25, 2015, at 2:53 AM, Markus Armbruster wrote: > Programmingkid <programmingk...@gmail.com> writes: > >> On Jun 23, 2015, at 2:06 PM, John Snow wrote: >> >>> >>> >>> On 06/23/2015 01:56 PM, Programmingkid wrote: >>>> Fix real cdrom detection so that a real cdrom can actually be used. >>>> >>>> signed-off-by: John Arbuckle <programmingk...@gmail.com >>>> <mailto:programmingk...@gmail.com>> >>>> >>>> This patch has been tested on Mac OS X host and guest. >>>> Command used: qemu-system-ppc -cdrom /dev/cdrom >>>> >>>> Note: I was able to view the files using OpenBIOS, but not on >>>> Mac OS X. The size of the disc is reported correctly but some >>>> error happens that prevents it from mounting in Mac OS X. This >>>> is probably another bug with QEMU. >>>> >>>> --- >>>> block.c | 3 ++- >>>> 1 files changed, 2 insertions(+), 1 deletions(-) >>>> >>>> diff --git a/block.c b/block.c >>>> index dd4f58d..75ccfad 100644 >>>> --- a/block.c >>>> +++ b/block.c >>>> @@ -583,7 +583,8 @@ static int find_image_format(BlockDriverState *bs, >>>> const char *filename, >>>> int ret = 0; >>>> >>>> >>>> >>>> /* Return the raw BlockDriver * to scsi-generic devices or empty >>>> drives */ >>>> - if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) { >>>> + if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0 >>>> + || strcmp("/dev/cdrom", filename) == 0) { >>>> *pdrv = &bdrv_raw; >>>> return ret; >>>> } >>>> -- >>>> 1.7.5.4 >>>> >>> >>> So what's the issue that this patch attempts to fix and how did you >>> determine that the fix was needed here? It doesn't look like it respects >>> proper abstraction at a glance. >> >> Without the patch, QEMU would just quit when the "-cdrom /dev/cdrom" >> option is given. >> >> Before the patch, the bdrv_open_inherit() function would be >> incorrectly called. Its documentation says "Opens a disk image (raw, >> qcow2, vmdk, ...)" meaning only for disk image files (not for real >> media). This patch prevents the bdrv_open_inherit() function from ever >> being called. It sets the pdrv variable to the raw format. This made >> sense to me since a real cdrom is read in the raw format. >> >> A quick test does show the patch works. A real cdrom is successfully >> opened on qemu-system-i386 using a Windows XP guest. > > What about /dev/sr0, /dev/sr1, and whatever other names could refer to a > block device without a medium? > > Comparing filenames isn't a good way to test "is a block device without > a medium".
I think we are going to have to agree to disagree. I have never used the /dev/sr(0 | 1) devices and don't see how they would be effected by this patch. Are you trying to say the /dev/sr(0 | 1) devices *should* be handled by this patch?
