From 864bd03c999c1b693eee27ed1043e818424432b4 Mon Sep 17 00:00:00 2001
From: Natalia Portillo <claunia@claunia.com>
Date: Wed, 24 Sep 2025 04:21:30 +0100
Subject: [PATCH] Implement READ PMA command.

---
 src/cdrom/cdrom.c         | 15 +++++++++++++++
 src/include/86box/cdrom.h |  1 +
 src/scsi/scsi_cdrom.c     |  5 +++++
 3 files changed, 21 insertions(+)

diff --git a/src/cdrom/cdrom.c b/src/cdrom/cdrom.c
index c59ba033d..4f2704f05 100644
--- a/src/cdrom/cdrom.c
+++ b/src/cdrom/cdrom.c
@@ -2149,6 +2149,21 @@ cdrom_get_current_subcodeq_playstatus(cdrom_t *dev, uint8_t *b)
     return ret;
 }
 
+int
+cdrom_read_pma(const cdrom_t *dev, uint8_t *b, const int max_len)
+{
+    if (max_len < 4)
+        return -1;
+
+    // This is exactly what a blank CD-R returns, no PMA, seems only CD-RWs have PMA?
+    b[0] = 0x00; /* PMA Data Length (MSB) */
+    b[1] = 0x02; /* PMA Data Length (LSB) */
+    b[2] = 0x00; /* Reserved */
+    b[3] = 0x00; /* Reserved */
+
+    return 4;
+}
+
 int
 cdrom_read_toc(const cdrom_t *dev, uint8_t *b, const int type,
                const uint8_t start_track, const int msf, const int max_len)
diff --git a/src/include/86box/cdrom.h b/src/include/86box/cdrom.h
index 9ab7e58cc..e13431c62 100644
--- a/src/include/86box/cdrom.h
+++ b/src/include/86box/cdrom.h
@@ -446,6 +446,7 @@ extern void            cdrom_get_current_subcodeq(cdrom_t *dev, uint8_t *b);
 extern uint8_t         cdrom_get_current_subcodeq_playstatus(cdrom_t *dev, uint8_t *b);
 extern int             cdrom_read_toc(const cdrom_t *dev, uint8_t *b, const int type,
                                       const uint8_t start_track, const int msf, const int max_len);
+extern int             cdrom_read_pma(const cdrom_t *dev, uint8_t *b, const int max_len);
 extern int             cdrom_read_toc_sony(const cdrom_t *dev, uint8_t *b, const uint8_t start_track,
                                            const int msf, const int max_len);
 #ifdef USE_CDROM_MITSUMI
diff --git a/src/scsi/scsi_cdrom.c b/src/scsi/scsi_cdrom.c
index 9dd5fb65d..c6e26c09a 100644
--- a/src/scsi/scsi_cdrom.c
+++ b/src/scsi/scsi_cdrom.c
@@ -2658,6 +2658,11 @@ scsi_cdrom_command(scsi_common_t *sc, const uint8_t *cdb)
                     scsi_cdrom_set_buf_len(dev, BufLen, &len);
                     scsi_cdrom_data_command_finish(dev, len, len, len, 0);
                 }
+            } else if (toc_format == 3 && dev->drv->cd_status == CD_STATUS_BLANK_CDR) {
+                len = cdrom_read_pma(dev->drv, dev->buffer, max_len);
+
+                scsi_cdrom_set_buf_len(dev, BufLen, &len);
+                scsi_cdrom_data_command_finish(dev, len, len, len, 0);
             } else
                 scsi_cdrom_invalid_field(dev, toc_format);
             break;