1============= 2Floppy Driver 3============= 4 5FAQ list: 6========= 7 8A FAQ list may be found in the fdutils package (see below), and also 9at <http://fdutils.linux.lu/faq.html>. 10 11 12LILO configuration options (Thinkpad users, read this) 13====================================================== 14 15The floppy driver is configured using the 'floppy=' option in 16lilo. This option can be typed at the boot prompt, or entered in the 17lilo configuration file. 18 19Example: If your kernel is called linux-2.6.9, type the following line 20at the lilo boot prompt (if you have a thinkpad):: 21 22 linux-2.6.9 floppy=thinkpad 23 24You may also enter the following line in /etc/lilo.conf, in the description 25of linux-2.6.9:: 26 27 append = "floppy=thinkpad" 28 29Several floppy related options may be given, example:: 30 31 linux-2.6.9 floppy=daring floppy=two_fdc 32 append = "floppy=daring floppy=two_fdc" 33 34If you give options both in the lilo config file and on the boot 35prompt, the option strings of both places are concatenated, the boot 36prompt options coming last. That's why there are also options to 37restore the default behavior. 38 39 40Module configuration options 41============================ 42 43If you use the floppy driver as a module, use the following syntax:: 44 45 modprobe floppy floppy="<options>" 46 47Example:: 48 49 modprobe floppy floppy="omnibook messages" 50 51If you need certain options enabled every time you load the floppy driver, 52you can put:: 53 54 options floppy floppy="omnibook messages" 55 56in a configuration file in /etc/modprobe.d/. 57 58 59The floppy driver related options are: 60 61 floppy=asus_pci 62 Sets the bit mask to allow only units 0 and 1. (default) 63 64 floppy=daring 65 Tells the floppy driver that you have a well behaved floppy controller. 66 This allows more efficient and smoother operation, but may fail on 67 certain controllers. This may speed up certain operations. 68 69 floppy=0,daring 70 Tells the floppy driver that your floppy controller should be used 71 with caution. 72 73 floppy=one_fdc 74 Tells the floppy driver that you have only one floppy controller. 75 (default) 76 77 floppy=two_fdc / floppy=<address>,two_fdc 78 Tells the floppy driver that you have two floppy controllers. 79 The second floppy controller is assumed to be at <address>. 80 This option is not needed if the second controller is at address 81 0x370, and if you use the 'cmos' option. 82 83 floppy=thinkpad 84 Tells the floppy driver that you have a Thinkpad. Thinkpads use an 85 inverted convention for the disk change line. 86 87 floppy=0,thinkpad 88 Tells the floppy driver that you don't have a Thinkpad. 89 90 floppy=omnibook / floppy=nodma 91 Tells the floppy driver not to use Dma for data transfers. 92 This is needed on HP Omnibooks, which don't have a workable 93 DMA channel for the floppy driver. This option is also useful 94 if you frequently get "Unable to allocate DMA memory" messages. 95 Indeed, dma memory needs to be continuous in physical memory, 96 and is thus harder to find, whereas non-dma buffers may be 97 allocated in virtual memory. However, I advise against this if 98 you have an FDC without a FIFO (8272A or 82072). 82072A and 99 later are OK. You also need at least a 486 to use nodma. 100 If you use nodma mode, I suggest you also set the FIFO 101 threshold to 10 or lower, in order to limit the number of data 102 transfer interrupts. 103 104 If you have a FIFO-able FDC, the floppy driver automatically 105 falls back on non DMA mode if no DMA-able memory can be found. 106 If you want to avoid this, explicitly ask for 'yesdma'. 107 108 floppy=yesdma 109 Tells the floppy driver that a workable DMA channel is available. 110 (default) 111 112 floppy=nofifo 113 Disables the FIFO entirely. This is needed if you get "Bus 114 master arbitration error" messages from your Ethernet card (or 115 from other devices) while accessing the floppy. 116 117 floppy=usefifo 118 Enables the FIFO. (default) 119 120 floppy=<threshold>,fifo_depth 121 Sets the FIFO threshold. This is mostly relevant in DMA 122 mode. If this is higher, the floppy driver tolerates more 123 interrupt latency, but it triggers more interrupts (i.e. it 124 imposes more load on the rest of the system). If this is 125 lower, the interrupt latency should be lower too (faster 126 processor). The benefit of a lower threshold is less 127 interrupts. 128 129 To tune the fifo threshold, switch on over/underrun messages 130 using 'floppycontrol --messages'. Then access a floppy 131 disk. If you get a huge amount of "Over/Underrun - retrying" 132 messages, then the fifo threshold is too low. Try with a 133 higher value, until you only get an occasional Over/Underrun. 134 It is a good idea to compile the floppy driver as a module 135 when doing this tuning. Indeed, it allows to try different 136 fifo values without rebooting the machine for each test. Note 137 that you need to do 'floppycontrol --messages' every time you 138 re-insert the module. 139 140 Usually, tuning the fifo threshold should not be needed, as 141 the default (0xa) is reasonable. 142 143 floppy=<drive>,<type>,cmos 144 Sets the CMOS type of <drive> to <type>. This is mandatory if 145 you have more than two floppy drives (only two can be 146 described in the physical CMOS), or if your BIOS uses 147 non-standard CMOS types. The CMOS types are: 148 149 == ================================== 150 0 Use the value of the physical CMOS 151 1 5 1/4 DD 152 2 5 1/4 HD 153 3 3 1/2 DD 154 4 3 1/2 HD 155 5 3 1/2 ED 156 6 3 1/2 ED 157 16 unknown or not installed 158 == ================================== 159 160 (Note: there are two valid types for ED drives. This is because 5 was 161 initially chosen to represent floppy *tapes*, and 6 for ED drives. 162 AMI ignored this, and used 5 for ED drives. That's why the floppy 163 driver handles both.) 164 165 floppy=unexpected_interrupts 166 Print a warning message when an unexpected interrupt is received. 167 (default) 168 169 floppy=no_unexpected_interrupts / floppy=L40SX 170 Don't print a message when an unexpected interrupt is received. This 171 is needed on IBM L40SX laptops in certain video modes. (There seems 172 to be an interaction between video and floppy. The unexpected 173 interrupts affect only performance, and can be safely ignored.) 174 175 floppy=broken_dcl 176 Don't use the disk change line, but assume that the disk was 177 changed whenever the device node is reopened. Needed on some 178 boxes where the disk change line is broken or unsupported. 179 This should be regarded as a stopgap measure, indeed it makes 180 floppy operation less efficient due to unneeded cache 181 flushings, and slightly more unreliable. Please verify your 182 cable, connection and jumper settings if you have any DCL 183 problems. However, some older drives, and also some laptops 184 are known not to have a DCL. 185 186 floppy=debug 187 Print debugging messages. 188 189 floppy=messages 190 Print informational messages for some operations (disk change 191 notifications, warnings about over and underruns, and about 192 autodetection). 193 194 floppy=silent_dcl_clear 195 Uses a less noisy way to clear the disk change line (which 196 doesn't involve seeks). Implied by 'daring' option. 197 198 floppy=<nr>,irq 199 Sets the floppy IRQ to <nr> instead of 6. 200 201 floppy=<nr>,dma 202 Sets the floppy DMA channel to <nr> instead of 2. 203 204 floppy=slow 205 Use PS/2 stepping rate:: 206 207 PS/2 floppies have much slower step rates than regular floppies. 208 It's been recommended that take about 1/4 of the default speed 209 in some more extreme cases. 210 211 212Supporting utilities and additional documentation: 213================================================== 214 215Additional parameters of the floppy driver can be configured at 216runtime. Utilities which do this can be found in the fdutils package. 217This package also contains a new version of mtools which allows to 218access high capacity disks (up to 1992K on a high density 3 1/2 disk!). 219It also contains additional documentation about the floppy driver. 220 221The latest version can be found at fdutils homepage: 222 223 http://fdutils.linux.lu 224 225The fdutils releases can be found at: 226 227 http://fdutils.linux.lu/download.html 228 229 http://www.tux.org/pub/knaff/fdutils/ 230 231 ftp://metalab.unc.edu/pub/Linux/utils/disk-management/ 232 233Reporting problems about the floppy driver 234========================================== 235 236If you have a question or a bug report about the floppy driver, mail 237me at Alain.Knaff@poboxes.com . If you post to Usenet, preferably use 238comp.os.linux.hardware. As the volume in these groups is rather high, 239be sure to include the word "floppy" (or "FLOPPY") in the subject 240line. If the reported problem happens when mounting floppy disks, be 241sure to mention also the type of the filesystem in the subject line. 242 243Be sure to read the FAQ before mailing/posting any bug reports! 244 245Alain 246 247Changelog 248========= 249 25010-30-2004 : 251 Cleanup, updating, add reference to module configuration. 252 James Nelson <james4765@gmail.com> 253 2546-3-2000 : 255 Original Document 256