Messages in this thread Patch in this message | | | Date | Wed, 28 May 2003 09:41:14 +0200 | From | Andy Polyakov <> | Subject | 2.5.69-70 ide-cd to guarantee fault-free CD/DVD burning experience? |
| |
Linux is setting new landmarks all the time. Linux 2.5 is taking CD/DVD burning to whole new level by *guaranteeing* fault-free burning experience. No more hassle with overburns, underruns, poorly supported media, positioning errors, power calibration failures, you name it... It just works [by keeping the user-land totally unaware of errors conditions raised by the logical unit]. Welcome to the future:-)
Well, I'm probably pushing this joke too far:-) In such case accept the apologies along with this patch which makes it possible to access the sense data returned by IDE CD/DVD units from user-land with SG_IO ioctl. As for the last part, req->data?req->data:req->buffer. I'm not sure if it's "the right thing(tm)" to do, but an error condition (dereferencing of NULL pointer to be specific) is raised otherwise, whenever call to bio_map_user in drivers/block/scsi_ioctl.c fails. The patch is applicable at least to 2.5.69 and 2.5.70.
As for 69-ac. SG_IO doesn't work there at all (kernel logs "confused, missing data" and then "N residual after xfer"). As far as I can tell drivers/block/scsi_ioctl.c needs a "face lift," but that's AC's(?) concern.
As for scsi_ioctl.c in more general sense. It apparently doesn't comply with SG HOWTO, in particular it mis-interprets time-out values. Background information and patch is available at http://fy.chalmers.se/~appro/linux/DVD+RW/scsi_ioctl-2.5.69.patch. There're couple of other issues, usage of 'bytes' variable in access_ok and DMA being off when bio_map_user fails, that needs some further discussion in my opinion. As for discussion. Please note that I'm not on the linux-kernel list so that keep me on Cc:.
Cheers. A. 8<--------8<--------8<--------8<--------8<--------8<--------8<-------- --- ./drivers/ide/ide-cd.c.orig Mon May 5 01:53:14 2003 +++ ./drivers/ide/ide-cd.c Mon May 26 17:06:09 2003 @@ -667,7 +667,8 @@ void *sense = &info->sense_data; if (failed && failed->sense) - sense = failed->sense; + sense = failed->sense, + failed->sense_len=rq->sense_len; cdrom_analyze_sense_data(drive, failed, sense); } @@ -723,7 +724,7 @@ * scsi status byte */ if ((rq->flags & REQ_BLOCK_PC) && !rq->errors) - rq->errors = CHECK_CONDITION; + rq->errors = CHECK_CONDITION<<1; /* Check for tray open. */ if (sense_key == NOT_READY) { @@ -1471,8 +1472,13 @@ /* Keep count of how much data we've moved. */ rq->data += thislen; rq->data_len -= thislen; +#if 0 if (rq->cmd[0] == GPCMD_REQUEST_SENSE) rq->sense_len++; +#else + if (rq->flags & REQ_SENSE) + rq->sense_len+=thislen; +#endif } else { confused: printk ("%s: cdrom_pc_intr: The drive " @@ -1609,7 +1615,7 @@ static void post_transform_command(struct request *req) { - char *ibuf = req->buffer; + char *ibuf = req->data?req->data:req->buffer; u8 *c = req->cmd; if (!blk_pc_request(req)) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |