Re: cdrom blocksize reset bug with 2.4.x kernels

[Tobias Diedrich <ranma@gmx.at>]

No comments on this?

I  wrote:
> As it seems Attila did not write a follow up, I had a look at his patch
> and the problem.  The following patch fixes it for me (Plextor PX-32TS).
> 
> Please CC me on replies, I am not subscribed to the list.
> 
> --- linux-2.4.22/include/linux/cdrom.h	2003-10-28 01:30:34.000000000 +0100
> +++ linux/include/linux/cdrom.h	2003-11-09 15:44:20.000000000 +0100
> @@ -743,7 +743,8 @@
>      	char name[20];                  /* name of the device type */
>  /* per-device flags */
>          __u8 sanyo_slot		: 2;	/* Sanyo 3 CD changer support */
> -        __u8 reserved		: 6;	/* not used yet */
> +        __u8 use_read10	: 1;		/* Use READ10 instead of READCD */
> +        __u8 reserved		: 5;	/* not used yet */
>  	struct cdrom_write_settings write;
>  };
>  
> --- linux-2.4.22/drivers/cdrom/cdrom.c	2003-11-07 23:46:49.000000000 +0100
> +++ linux/drivers/cdrom/cdrom.c	2003-11-09 15:52:14.000000000 +0100
> @@ -1400,6 +1400,8 @@
>  	return 0;
>  }
>  
> +static int cdrom_switch_blocksize(struct cdrom_device_info *cdi, int size);
> +
>  /*
>   * Specific READ_10 interface
>   */
> @@ -1408,6 +1410,7 @@
>  			 int blocksize, int nblocks)
>  {
>  	struct cdrom_device_ops *cdo = cdi->ops;
> +	int ret = 0;
>  
>  	memset(&cgc->cmd, 0, sizeof(cgc->cmd));
>  	cgc->cmd[0] = GPCMD_READ_10;
> @@ -1419,7 +1422,22 @@
>  	cgc->cmd[7] = (nblocks >>  8) & 0xff;
>  	cgc->cmd[8] = nblocks & 0xff;
>  	cgc->buflen = blocksize * nblocks;
> -	return cdo->generic_packet(cdi, cgc);
> +
> +	if (blocksize != CD_FRAMESIZE) {
> +		ret = cdrom_switch_blocksize(cdi, blocksize);
> +		ret |= cdo->generic_packet(cdi, cgc);
> +		ret |= cdrom_switch_blocksize(cdi, CD_FRAMESIZE);
> +	} else ret = cdo->generic_packet(cdi, cgc);
> +
> +	/*
> +	 * Switch cdrom_read_block back to default behaviour
> +	 * if we get an error.
> +	 * FIXME: Maybe this should not be done on all errors.
> +	 */
> +	if (ret != 0)
> +		cdi->use_read10 = 0;
> +
> +	return ret;
>  }
>  
>  /* very generic interface for reading the various types of blocks */
> @@ -1428,8 +1446,15 @@
>  			    int lba, int nblocks, int format, int blksize)
>  {
>  	struct cdrom_device_ops *cdo = cdi->ops;
> +	int ret;
> +
> +	if (cdi->use_read10)
> +		return cdrom_read_cd(cdi, cgc, lba, blksize, nblocks);
>  
>  	memset(&cgc->cmd, 0, sizeof(cgc->cmd));
> +	/*
> +	 * SCSI-II devices are not required to support READ_CD.
> +	 */
>  	cgc->cmd[0] = GPCMD_READ_CD;
>  	/* expected sector size - cdda,mode1,etc. */
>  	cgc->cmd[1] = format << 2;
> @@ -1452,7 +1477,15 @@
>  	default			: cgc->cmd[9] = 0x10;
>  	}
>  	
> -	return cdo->generic_packet(cdi, cgc);
> +	ret = cdo->generic_packet(cdi, cgc);
> +	if (ret && cgc->sense && cgc->sense->sense_key==0x05 && cgc->sense->asc==0x20 && cgc->sense->ascq==0x00) {
> +		ret = cdrom_read_cd(cdi, cgc, lba, blksize, nblocks);
> +		if (ret == 0) {
> +			cdi->use_read10 = 1;
> +			printk(KERN_INFO "cdrom.c: drive does not like READ_CD for blksize=%d, switching to READ_10.\n", blksize);
> +		}
> +	}
> +	return ret;
>  }
>  
>  /* Just about every imaginable ioctl is supported in the Uniform layer
> @@ -1956,20 +1989,6 @@
>  		cgc.sense = &sense;
>  		cgc.data_direction = CGC_DATA_READ;
>  		ret = cdrom_read_block(cdi, &cgc, lba, 1, format, blocksize);
> -		if (ret && sense.sense_key==0x05 && sense.asc==0x20 && sense.ascq==0x00) {
> -			/*
> -			 * SCSI-II devices are not required to support
> -			 * READ_CD, so let's try switching block size
> -			 */
> -			/* FIXME: switch back again... */
> -			if ((ret = cdrom_switch_blocksize(cdi, blocksize))) {
> -				kfree(cgc.buffer);
> -				return ret;
> -			}
> -			cgc.sense = NULL;
> -			ret = cdrom_read_cd(cdi, &cgc, lba, blocksize, 1);
> -			ret |= cdrom_switch_blocksize(cdi, blocksize);
> -		}
>  		if (!ret && copy_to_user((char *)arg, cgc.buffer, blocksize))
>  			ret = -EFAULT;
>  		kfree(cgc.buffer);
> 
> -- 
> Tobias						PGP: http://9ac7e0bc.2ya.com

-- 
Tobias						PGP: http://9ac7e0bc.2ya.com
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