Re: [Libcdio-devel] Re: Submission of new mmc function for libcdio

[Rocky Bernstein]

Yes, I think libcdio should have a mmc_get_discmode, so additions are most
welcome here.

I had thought recent work that Thomas added here covered this, but I don't
see it. Perhaps I was thinking about information he recently added to the
libcdio glossary under "Media models and profiles" which may be of some
help?


On Wed, Jan 27, 2010 at 1:10 PM, Frank Endres <address@hidden>wrote:

> Hi !
>
> I use libcdio for only a short time, and found it easy to use (good
> examples
> and documentation), except for mmc commands. Now, after long searches, I
> have understood how it works, and I have a suggestion:
> add a link to "http://www.13thmonkey.org/documentation/SCSI/mmc-r10a.pdf,";
> on your doc (mmc.h - if not already done, maybe I haven't looked in the
> right place).
>
> I want to use libcdio as an alternate method for device and media detection
> in my SimpleBurn project (http://simpleburn.tuxfamily.org - wait untill
> next
> version to have that libcdio detection feature). I wanted a function to
> tell
> me if a CD is rewritable or not, and didn't find it, so I wrote one (I have
> seen no other solution than using a mmc command); if you find it usefull,
> you can add it into libcdio:
>
> /*!
>   Detects if a disc (CD or DVD) is erasable or not.
>   See http://www.13thmonkey.org/documentation/SCSI/mmc-r10a.pdf, tables
> 129-134.
>   @return true if the disc is erasable (rewritable), false otherwise.
>  */
> bool
> mmc_get_disc_erasable ( const CdIo_t *p_cdio) {
>  mmc_cdb_t cdb = {{0, }};
>
>  uint8_t buf[42] = { 0, };
>
>  CDIO_MMC_SET_COMMAND (cdb.field, CDIO_MMC_GPCMD_READ_DISC_INFO);
>  CDIO_MMC_SET_READ_LENGTH8 (cdb.field, sizeof(buf));
>
>  mmc_run_cmd (p_cdio, 0, &cdb, SCSI_MMC_DATA_READ, sizeof(buf), &buf);
>
>  if (buf[2] & 0x10) //works even if the 'mmc_run_cmd' command fails
>    return true;
>  else
>    return false;
> }
>
> If I have understood the source, even cdw doesn't use libcdio to detect a
> device type (it uses dvd+rw-tools or cdrtools output I guess). It could be
> interesting to add a feature to get more information on discs: (add some
> values to (mmc)discmode_t enumeration for example: CDIO_DISC_MODE_CD_R,
> CDIO_DISC_MODE_CD_RW, CDIO_DISC_MODE_CD_ROM), and a new function like:
> "mmcdiscmode_t mmc_get_discmode (CdIo *p_cdio)". Tell me if you are
> interested in this feature.
>
> Best regards !
>
> Frank Endres
>