New cdrskin option --bdr_obs_exempt

cdrskin/cdrskin.1

@@ -2,7 +2,7 @@
 .\" First parameter, NAME, should be all caps
 .\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
 .\" other parameters are allowed: see man(7), man(1)
-.TH CDRSKIN 1 "Version 1.5.5, Jun 29, 2021"
+.TH CDRSKIN 1 "Version 1.5.5, Sep 12, 2021"
 .\" Please adjust this date whenever revising the manpage.
 .\"
 .\" Some roff macros, for reference:
@@ -1640,16 +1640,27 @@ addresses which are not listed with cdrskin --devices but nevertheless point
 to a usable drive. (Like /dev/sg0 using the same SCSI address as /dev/sr0.)
 .TP
 .BI \--obs_pad
-Pad the data of last write operation of a DVD-R[W] DAO session or
-stdio: pseudo-drive up to the full size of an output chunk.
+Pad the data of the last write operation of a DVD-R[W] DAO session, or BD-R
+session, or stdio: pseudo-drive session up to the full size of an output chunk.
 This padding has to be applied automatically to the other DVD and BD media
 types, where it causes e.g. ISO images to have trailing unclaimed blocks.
+Whether it is applied automatically to BD-R depends on option
+--bdr_obs_exempt.
 .br
-Use this option if there is the suspicion that DAO sessions abort with
-your kernel and/or DVD drive, if their size is not a multiple of 16 blocks.
+Use this option if there is the suspicion that DVD-R[W] DAO or BD-R sessions 
+abort with your kernel and/or DVD drive, if their size is not a multiple of 
+16 blocks.
 .br
 This option may also get enabled at compile time of libburn.
 .TP
+.BI \--bdr_obs_exempt
+Exempt BD-R media from automatic unconditional transaction end padding,
+provided that this padding is not requested by --obs_pad and that
+no stream_recording is requested.
+.br
+This is a new feature introduced with version 1.5.6. It might become default
+in later versions.
+.TP
 .BI \--old_pseudo_scsi_adr
 Linux specific:
 Use and report literal Bus,Target,Lun addresses rather than real SCSI and

cdrskin/cdrskin.c

@@ -2914,6 +2914,8 @@ set_dev:;
      printf(
          " --no_rc            as first argument: do not read startup files\n");
      printf(" --obs_pad          pad DVD DAO to full 16 or 32 blocks\n");
+     printf(
+        " --bdr_obs_exempt   possibly exempt BD-R from padding to full 64k\n");
      printf(" --old_pseudo_scsi_adr  use and report literal Bus,Target,Lun\n");
      printf("                    rather than real SCSI and pseudo ATA.\n");
      printf(
@@ -3391,6 +3393,9 @@ struct CdrskiN {
  int stream_recording_is_set; /* see burn_write_opts_set_stream_recording() */
  int dvd_obs;                 /* DVD write chunk size: 0, 32k or 64k */
  int obs_pad;                 /* Whether to force obs end padding */
+ int bdr_obs_exempt;          /* Whether to possibly exempt BD-R from automatic
+                                 obs_pad
+                               */
  int stdio_sync;              /* stdio fsync interval: -1, 0, >=32 */
  int single_track;
  int prodvd_cli_compatible;
@@ -3665,6 +3670,7 @@ int Cdrskin_new(struct CdrskiN **skin, struct CdrpreskiN *preskin, int flag)
  o->stream_recording_is_set= 0;
  o->dvd_obs= 0;
  o->obs_pad= 0;
+ o->bdr_obs_exempt= 0;
  o->stdio_sync= 0;
  o->single_track= 0;
  o->prodvd_cli_compatible= 0;
@@ -7697,6 +7703,7 @@ burn_failed:;
 #endif
    burn_write_opts_set_dvd_obs(o, skin->dvd_obs);
  burn_write_opts_set_obs_pad(o, skin->obs_pad);
+ burn_write_opts_set_bdr_obs_exempt(o, skin->bdr_obs_exempt);
  burn_write_opts_set_stdio_fsync(o, skin->stdio_sync);
 
  if(skin->dummy_mode) {
@@ -9169,6 +9176,9 @@ msifile_equals:;
    } else if(strcmp(argv[i],"--obs_pad")==0) {
      skin->obs_pad= 1;
 
+   } else if(strcmp(argv[i],"--bdr_obs_exempt")==0) {
+     skin->bdr_obs_exempt= 1;
+
    } else if(strcmp(argv[i],"--old_pseudo_scsi_adr")==0) {
      /* is handled in Cdrpreskin_setup() */;
 

cdrskin/cdrskin_timestamp.h

@@ -1 +1 @@
-#define Cdrskin_timestamP "2021.09.02.181259"
+#define Cdrskin_timestamP "2021.09.12.084556"

libburn/libburn.h

@@ -3389,6 +3389,21 @@ void burn_write_opts_set_dvd_obs(struct burn_write_opts *opts, int obs);
 void burn_write_opts_set_obs_pad(struct burn_write_opts *opts, int pad);
 
 
+/* ts C10909 */
+/** Exempts BD-R media from the elsewise unavoidable automatic padding of the
+    last write chunk to its full size.
+    Even if this exempt is granted it gets into effect only if stream recording
+    is disabled and burn_write_opts_set_obs_pad() is set to 0.
+    @param opts The write opts to change
+    @param value  1= possibly exempt BD-R from end chunk padding.
+                  0= always act on BD-R as if
+                     burn_write_opts_set_obs_pad(opts, 1) is in effect.
+    @since 1.5.6
+*/
+void burn_write_opts_set_bdr_obs_exempt(struct burn_write_opts *opts,
+                                        int value);
+
+
 /* ts A91115 */
 /** Sets the rhythm by which stdio pseudo drives force their output data to
     be consumed by the receiving storage device. This forcing keeps the memory

libburn/libburn.ver

@@ -186,6 +186,7 @@ burn_write_opts_auto_write_type;
 burn_write_opts_free;
 burn_write_opts_get_drive;
 burn_write_opts_new;
+burn_write_opts_set_bdr_obs_exempt;
 burn_write_opts_set_dvd_obs;
 burn_write_opts_set_fail21h_sev;
 burn_write_opts_set_fillup;

libburn/options.c

@@ -55,6 +55,7 @@ struct burn_write_opts *burn_write_opts_new(struct burn_drive *drive)
 	opts->obs_pad = 0;
 #endif
 
+	opts->bdr_obs_exempt = 0;
 	opts->start_byte = -1;
 	opts->fill_up_media = 0;
 	opts->force_is_set = 0;
@@ -535,6 +536,14 @@ void burn_write_opts_set_obs_pad(struct burn_write_opts *opts, int pad)
 }
 
 
+/* ts C10909: API */
+void burn_write_opts_set_bdr_obs_exempt(struct burn_write_opts *opts,
+					int value)
+{
+	opts->bdr_obs_exempt = !!value;
+}
+
+
 /* ts A91115: API */
 void burn_write_opts_set_stdio_fsync(struct burn_write_opts *opts, int rhythm)
 {

libburn/options.h

@@ -46,6 +46,9 @@ struct burn_write_opts
 	                2 indicates burn_write_opts_set_obs_pad(,1)
 	             */
 
+	/* 1= do not apply obs_pad=1 to BD-R if not stream recording. */
+	int bdr_obs_exempt;
+
 	/* ts A61222 : Start address for media which offer a choice */
 	off_t start_byte;
 

libburn/write.c

@@ -1658,16 +1658,6 @@ int burn_disc_open_track_dvd_plus_r(struct burn_write_opts *o,
 				size += (off_t) (o->obs - (size % o->obs));
 		}
 
-		/* <<< Only for now until the first DVD+R succeeded */
-		if (!o->obs_pad) {
-			sprintf(msg, "Program error: encountered DVD+R without chunk padding");
-			libdax_msgs_submit(libdax_messenger, d->global_index,
-				0x00000004,
-				LIBDAX_MSGS_SEV_FATAL, LIBDAX_MSGS_PRIO_HIGH,
-				msg, 0, 0);
-			{ret = 0; goto ex;}
-		}
-
 		ret = d->reserve_track(d, size);
 		if (ret <= 0) {
 			sprintf(msg, "Cannot reserve track of %.f bytes",
@@ -2436,9 +2426,17 @@ int burn_dvd_write_sync(struct burn_write_opts *o,
 				msg, 0, 0);
 			goto early_failure;
 		}
-		/* ??? padding needed ??? cowardly doing it for now */
-		if (o->obs_pad < 2)
+		/* Unaligned BD-R track end works with various drives and
+		   produces exact READ CAPACITY results.
+		   Nevertheless stream recording hates unaligned WRITE.
+		   With DVD+R it seems that obs_pad is silently applied by the
+		   drive if a non-aligned final WRITE is received.
+		*/
+		if (o->obs_pad < 2 &&
+		    !(d->current_profile == 0x41 && !d->do_stream_recording &&
+		      o->bdr_obs_exempt))
 			o->obs_pad = 1; /* fill-up track's last obs buffer */
+
 		if (d->current_profile == 0x41) /* BD-R */
 			o->obs = Libburn_bd_r_obS;
 		if (d->do_stream_recording) {