Messages in this thread | | | Date | Sun, 19 Feb 2006 01:46:49 -0500 | From | linuxer@ever ... | Subject | Re: pktcdvd DVD+RW always writes at max drive speed (not media speed) |
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Phillip Susi <psusi@cfl.rr.com> wrote:
> > I thought that the code asked the drive for the max supported speed _for > the loaded media_. I know I've been using pktcdvd without problem on > cdrw media that is only rated for 4x on drives that support 12x or 16x, > and based on the performance I've been seeing, it is only burning at 4x. > Maybe your drive isn't reporting properly? >
As I stated clearly before, I am having this problem with DVD+RW media. The relevant code in pktcdvd.c (in function pkt_open_write) is:
if ((ret = pkt_get_max_speed(pd, &write_speed))) write_speed = 16 * 177; switch (pd->mmc3_profile) { case 0x13: /* DVD-RW */ case 0x1a: /* DVD+RW */ case 0x12: /* DVD-RAM */ DPRINTK("pktcdvd: write speed %ukB/s\n", write_speed); break; default: if ((ret = pkt_media_speed(pd, &media_write_speed))) media_write_speed = 16; write_speed = min(write_speed, media_write_speed * 177); DPRINTK("pktcdvd: write speed %ux\n", write_speed / 176); break; } read_speed = write_speed;
if ((ret = pkt_set_speed(pd, write_speed, read_speed))) { DPRINTK("pktcdvd: %s couldn't set write speed\n", pd->name); return -EIO; }
As you can see, in the case of DVD+RW, the speed is set to the value stored to write_speed by the function pkt_get_max_speed, whose documented purpose (according to comments) is to return the drives reported maximum rewrite speed capability. pkt_media_speed is only called in the case of CD-RW's. In fact, it returns an error if the media is not CD-RW.
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