diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c
index 0bfeb0c..690475b 100644
--- a/drivers/ide/ide-cd.c
+++ b/drivers/ide/ide-cd.c
@@ -194,6 +194,14 @@
 			bio_sectors = max(bio_sectors(failed_command->bio), 4U);
 			sector &= ~(bio_sectors - 1);
 
+			/*
+			 * The SCSI specification allows for the value
+			 * returned by READ CAPACITY to be up to 75 2K
+			 * sectors past the last readable block.
+			 * Therefore, if we hit a medium error within the
+			 * last 75 2K sectors, we decrease the saved size
+			 * value.
+			 */
 			if (sector < get_capacity(info->disk) &&
 			    drive->probed_capacity - sector < 4 * 75)
 				set_capacity(info->disk, sector);