Kernel parameters for hda/sr0 support

[arcanis]

I'm attempting to make an image with buildroot, but /dev/sr0 and /dev/hda (or /dev/sda) are missing. I tried to tweak my kernel parameters (see here) to no avail. Do you know which parameters are necessary for cdroms or hard drives to be supported?

I note the same is true in the Buildroot image available in the demos: inserting a cdrom doesn't seem to work (or I'm not looking at the right place, maybe?).

[SuperMaxusa]

Can you show dmesg | grep ata (in v86 and QEMU)?

[chschnell]

I think these parameters should do: https://www.linuxtopia.org/online_books/linux_kernel/kernel_configuration/ch09.html#lkn_ide (note the section "IDE CD-ROM drives").

We need support for a PCI IDE controller, ATA for harddisks and ATAPI for CD-RWs (which pulls in some support for SCSI). The PCI controller in V86 declares itself to be a "Intel 82371SB PIIX3 IDE [Natoma/Triton II]" in the PCI space.

I could give it a try on the weekend unless you get it to work.

---

EDIT: That guide is completely outdated. However, I played around with make linux-menuconfig and got this (booted with a mounted 64M blank HD and some CDROM disk):

~% dmesg | grep -Ei "(scsi|ata)"
Memory: 2048112K/2080248K available (5497K kernel code, 701K rwdata, 1176K rodata, 6512K init, 304K bss, 32136K reserved, 0K cma-reserved, 1175432K highmem)
MMIO Stale Data: Unknown: No mitigations
SCSI subsystem initialized
libata version 3.00 loaded.
Block layer SCSI generic (bsg) driver version 0.4 loaded (major 254)
ata_piix 0000:00:1e.0: version 2.13
scsi host0: ata_piix
scsi host1: ata_piix
ata1: PATA max MWDMA2 cmd 0x1f0 ctl 0x3f6 bmdma 0xc070 irq 14 lpm-pol 0
ata2: PATA max MWDMA2 cmd 0x170 ctl 0x376 bmdma 0xc078 irq 15 lpm-pol 0
ata1.00: ATA-0: v86 ATA HD, 1.00, max MWDMA2
ata1.00: 131072 sectors, multi 0: LBA48
scsi 0:0:0:0: Direct-Access     ATA      v86 ATA HD       n/a  PQ: 0 ANSI: 5
ata2.00: ATAPI: v86 ATAPI CD-ROM, 1.00, max MWDMA2
scsi 1:0:0:0: CD-ROM            SONY     CD-ROM CDU-1000  1.1a PQ: 0 ANSI: 1 CCS
Write protecting kernel text and read-only data: 6676k

The kernel detects both our drives at their correct IDE locations:

ata1.00: ATA-0: v86 ATA HD, 1.00, max MWDMA2
ata2.00: ATAPI: v86 ATAPI CD-ROM, 1.00, max MWDMA2

but for some reason nothing shows up under /dev.

---

EDIT 2: Just noticed that /dev/sr0 works here (/dev/sda is however still missing):

~% ls /dev/sr0
/dev/sr0
~% mount /dev/sr0 /media/
~% ls /media/
Copyright                    Solaris_11
JDS-THIRDPARTYLICENSEREADME  installer
~%

[arcanis]

It works, thanks a lot !

[chschnell]

All right, here is what needs to be changed in the linux kernel configuration for floppy, harddisk and cdrom support.

Run make linux-menuconfig and enable all these:

• CONFIG_ATA
• CONFIG_ATA_PIIX
• CONFIG_ATA_GENERIC
• CONFIG_BLK_DEV_FD
• CONFIG_BLK_DEV_SD
• CONFIG_BLK_DEV_SR
• CONFIG_EXT2_FS
• CONFIG_MSDOS_FS
• CONFIG_VFAT_FS
• CONFIG_NLS_CODEPAGE_437
• CONFIG_JOLIET

I tested /dev/sda[1] and /dev/sdb[1] using images formatted with ext2 (Debian 2GB) and msdos (FreeDOS 20M) file systems. I also tested /dev/sr0 with different ISOs.

I added file system support as needed (CONFIG_NLS_CODEPAGE_437 is needed for DOS images, CONFIG_JOLIET is rare but doesn't hurt).

I did not add any automount extras, from what I understand that would be done using mdev (a small replacement for udev).

Output of blkid and fdisk:

~% blkid
/dev/sda1: UUID="0183c437-f29e-4fa7-95cc-89a9ca858a54"
/dev/sdb1: LABEL="FREEDOS2025" UUID="4049-1B0E"
~%
~% fdisk -l
Disk /dev/sda: 2047 MB, 2146435072 bytes, 4192256 sectors
8220 cylinders, 255 heads, 2 sectors/track
Units: sectors of 1 * 512 = 512 bytes

Device  Boot StartCHS    EndCHS        StartLBA     EndLBA    Sectors  Size Id Type
/dev/sda1 *  4,4,1       1023,254,2        2048    4190207    4188160 2045M 83 Linux
Disk /dev/sdb: 20 MB, 20971520 bytes, 40960 sectors
40 cylinders, 16 heads, 63 sectors/track
Units: sectors of 1 * 512 = 512 bytes

Device  Boot StartCHS    EndCHS        StartLBA     EndLBA    Sectors  Size Id Type
/dev/sdb1 *  0,1,1       39,15,63            63      40319      40257 19.6M  4 FAT16 <32M

See here for the buildroot bzImage and config files.

EDIT: Here is the diff of the linux kernel's .config:

diff config-linux_20250210.txt config-linux_20251011.txt

$ diff config-linux_20250210.txt config-linux_20251011.txt
1000c1000,1002
< # CONFIG_BLK_DEV_FD is not set
---
> CONFIG_BLK_DEV_FD=y
> # CONFIG_BLK_DEV_FD_RAWCMD is not set
> CONFIG_CDROM=y
1074c1076
< # CONFIG_BLK_DEV_SD is not set
---
> CONFIG_BLK_DEV_SD=y
1076c1078
< # CONFIG_BLK_DEV_SR is not set
---
> CONFIG_BLK_DEV_SR=y
1151c1153,1250
< # CONFIG_ATA is not set
---
> CONFIG_ATA=y
> CONFIG_SATA_HOST=y
> CONFIG_PATA_TIMINGS=y
> CONFIG_ATA_VERBOSE_ERROR=y
> CONFIG_ATA_FORCE=y
> CONFIG_ATA_ACPI=y
> CONFIG_SATA_PMP=y
>
> #
> # Controllers with non-SFF native interface
> #
> # CONFIG_SATA_AHCI is not set
> # CONFIG_SATA_AHCI_PLATFORM is not set
> # CONFIG_AHCI_DWC is not set
> # CONFIG_SATA_INIC162X is not set
> # CONFIG_SATA_ACARD_AHCI is not set
> # CONFIG_SATA_SIL24 is not set
> CONFIG_ATA_SFF=y
>
> #
> # SFF controllers with custom DMA interface
> #
> # CONFIG_PDC_ADMA is not set
> # CONFIG_SATA_QSTOR is not set
> # CONFIG_SATA_SX4 is not set
> CONFIG_ATA_BMDMA=y
>
> #
> # SATA SFF controllers with BMDMA
> #
> CONFIG_ATA_PIIX=y
> # CONFIG_SATA_MV is not set
> # CONFIG_SATA_NV is not set
> # CONFIG_SATA_PROMISE is not set
> # CONFIG_SATA_SIL is not set
> # CONFIG_SATA_SIS is not set
> # CONFIG_SATA_SVW is not set
> # CONFIG_SATA_ULI is not set
> # CONFIG_SATA_VIA is not set
> # CONFIG_SATA_VITESSE is not set
>
> #
> # PATA SFF controllers with BMDMA
> #
> # CONFIG_PATA_ALI is not set
> # CONFIG_PATA_AMD is not set
> # CONFIG_PATA_ARTOP is not set
> # CONFIG_PATA_ATIIXP is not set
> # CONFIG_PATA_ATP867X is not set
> # CONFIG_PATA_CMD64X is not set
> # CONFIG_PATA_CS5520 is not set
> # CONFIG_PATA_CS5530 is not set
> # CONFIG_PATA_CS5535 is not set
> # CONFIG_PATA_CS5536 is not set
> # CONFIG_PATA_CYPRESS is not set
> # CONFIG_PATA_EFAR is not set
> # CONFIG_PATA_HPT366 is not set
> # CONFIG_PATA_HPT37X is not set
> # CONFIG_PATA_HPT3X2N is not set
> # CONFIG_PATA_HPT3X3 is not set
> # CONFIG_PATA_IT8213 is not set
> # CONFIG_PATA_IT821X is not set
> # CONFIG_PATA_JMICRON is not set
> # CONFIG_PATA_MARVELL is not set
> # CONFIG_PATA_NETCELL is not set
> # CONFIG_PATA_NINJA32 is not set
> # CONFIG_PATA_NS87415 is not set
> # CONFIG_PATA_OLDPIIX is not set
> # CONFIG_PATA_OPTIDMA is not set
> # CONFIG_PATA_PDC2027X is not set
> # CONFIG_PATA_PDC_OLD is not set
> # CONFIG_PATA_RADISYS is not set
> # CONFIG_PATA_RDC is not set
> # CONFIG_PATA_SC1200 is not set
> # CONFIG_PATA_SCH is not set
> # CONFIG_PATA_SERVERWORKS is not set
> # CONFIG_PATA_SIL680 is not set
> # CONFIG_PATA_SIS is not set
> # CONFIG_PATA_TOSHIBA is not set
> # CONFIG_PATA_TRIFLEX is not set
> # CONFIG_PATA_VIA is not set
> # CONFIG_PATA_WINBOND is not set
>
> #
> # PIO-only SFF controllers
> #
> # CONFIG_PATA_CMD640_PCI is not set
> # CONFIG_PATA_MPIIX is not set
> # CONFIG_PATA_NS87410 is not set
> # CONFIG_PATA_OPTI is not set
> # CONFIG_PATA_RZ1000 is not set
>
> #
> # Generic fallback / legacy drivers
> #
> # CONFIG_PATA_ACPI is not set
> CONFIG_ATA_GENERIC=y
> # CONFIG_PATA_LEGACY is not set
1915c2014,2016
< # CONFIG_EXT2_FS is not set
---
> CONFIG_LEGACY_DIRECT_IO=y
> CONFIG_EXT2_FS=y
> # CONFIG_EXT2_FS_XATTR is not set
1920d2020
< CONFIG_EXT4_USE_FOR_EXT2=y
1962c2062
< # CONFIG_JOLIET is not set
---
> CONFIG_JOLIET=y
1970,1971c2070,2075
< # CONFIG_MSDOS_FS is not set
< # CONFIG_VFAT_FS is not set
---
> CONFIG_FAT_FS=y
> CONFIG_MSDOS_FS=y
> CONFIG_VFAT_FS=y
> CONFIG_FAT_DEFAULT_CODEPAGE=437
> CONFIG_FAT_DEFAULT_IOCHARSET="iso8859-1"
> # CONFIG_FAT_DEFAULT_UTF8 is not set
2010c2114
< # CONFIG_NLS_CODEPAGE_437 is not set
---
> CONFIG_NLS_CODEPAGE_437=y
2360a2465,2466
> CONFIG_GLOB=y
> # CONFIG_GLOB_SELFTEST is not set