Based on kernel version 4.2. Page generated on 2015-09-09 12:08 EST.
1 This file describes the floppy driver. 2 3 FAQ list: 4 ========= 5 6 A FAQ list may be found in the fdutils package (see below), and also 7 at <http://fdutils.linux.lu/faq.html>. 8 9 10 LILO configuration options (Thinkpad users, read this) 11 ====================================================== 12 13 The floppy driver is configured using the 'floppy=' option in 14 lilo. This option can be typed at the boot prompt, or entered in the 15 lilo configuration file. 16 17 Example: If your kernel is called linux-2.6.9, type the following line 18 at the lilo boot prompt (if you have a thinkpad): 19 20 linux-2.6.9 floppy=thinkpad 21 22 You may also enter the following line in /etc/lilo.conf, in the description 23 of linux-2.6.9: 24 25 append = "floppy=thinkpad" 26 27 Several floppy related options may be given, example: 28 29 linux-2.6.9 floppy=daring floppy=two_fdc 30 append = "floppy=daring floppy=two_fdc" 31 32 If you give options both in the lilo config file and on the boot 33 prompt, the option strings of both places are concatenated, the boot 34 prompt options coming last. That's why there are also options to 35 restore the default behavior. 36 37 38 Module configuration options 39 ============================ 40 41 If you use the floppy driver as a module, use the following syntax: 42 modprobe floppy floppy="<options>" 43 44 Example: 45 modprobe floppy floppy="omnibook messages" 46 47 If you need certain options enabled every time you load the floppy driver, 48 you can put: 49 50 options floppy floppy="omnibook messages" 51 52 in a configuration file in /etc/modprobe.d/. 53 54 55 The floppy driver related options are: 56 57 floppy=asus_pci 58 Sets the bit mask to allow only units 0 and 1. (default) 59 60 floppy=daring 61 Tells the floppy driver that you have a well behaved floppy controller. 62 This allows more efficient and smoother operation, but may fail on 63 certain controllers. This may speed up certain operations. 64 65 floppy=0,daring 66 Tells the floppy driver that your floppy controller should be used 67 with caution. 68 69 floppy=one_fdc 70 Tells the floppy driver that you have only one floppy controller. 71 (default) 72 73 floppy=two_fdc 74 floppy=<address>,two_fdc 75 Tells the floppy driver that you have two floppy controllers. 76 The second floppy controller is assumed to be at <address>. 77 This option is not needed if the second controller is at address 78 0x370, and if you use the 'cmos' option. 79 80 floppy=thinkpad 81 Tells the floppy driver that you have a Thinkpad. Thinkpads use an 82 inverted convention for the disk change line. 83 84 floppy=0,thinkpad 85 Tells the floppy driver that you don't have a Thinkpad. 86 87 floppy=omnibook 88 floppy=nodma 89 Tells the floppy driver not to use Dma for data transfers. 90 This is needed on HP Omnibooks, which don't have a workable 91 DMA channel for the floppy driver. This option is also useful 92 if you frequently get "Unable to allocate DMA memory" messages. 93 Indeed, dma memory needs to be continuous in physical memory, 94 and is thus harder to find, whereas non-dma buffers may be 95 allocated in virtual memory. However, I advise against this if 96 you have an FDC without a FIFO (8272A or 82072). 82072A and 97 later are OK. You also need at least a 486 to use nodma. 98 If you use nodma mode, I suggest you also set the FIFO 99 threshold to 10 or lower, in order to limit the number of data 100 transfer interrupts. 101 102 If you have a FIFO-able FDC, the floppy driver automatically 103 falls back on non DMA mode if no DMA-able memory can be found. 104 If you want to avoid this, explicitly ask for 'yesdma'. 105 106 floppy=yesdma 107 Tells the floppy driver that a workable DMA channel is available. 108 (default) 109 110 floppy=nofifo 111 Disables the FIFO entirely. This is needed if you get "Bus 112 master arbitration error" messages from your Ethernet card (or 113 from other devices) while accessing the floppy. 114 115 floppy=usefifo 116 Enables the FIFO. (default) 117 118 floppy=<threshold>,fifo_depth 119 Sets the FIFO threshold. This is mostly relevant in DMA 120 mode. If this is higher, the floppy driver tolerates more 121 interrupt latency, but it triggers more interrupts (i.e. it 122 imposes more load on the rest of the system). If this is 123 lower, the interrupt latency should be lower too (faster 124 processor). The benefit of a lower threshold is less 125 interrupts. 126 127 To tune the fifo threshold, switch on over/underrun messages 128 using 'floppycontrol --messages'. Then access a floppy 129 disk. If you get a huge amount of "Over/Underrun - retrying" 130 messages, then the fifo threshold is too low. Try with a 131 higher value, until you only get an occasional Over/Underrun. 132 It is a good idea to compile the floppy driver as a module 133 when doing this tuning. Indeed, it allows to try different 134 fifo values without rebooting the machine for each test. Note 135 that you need to do 'floppycontrol --messages' every time you 136 re-insert the module. 137 138 Usually, tuning the fifo threshold should not be needed, as 139 the default (0xa) is reasonable. 140 141 floppy=<drive>,<type>,cmos 142 Sets the CMOS type of <drive> to <type>. This is mandatory if 143 you have more than two floppy drives (only two can be 144 described in the physical CMOS), or if your BIOS uses 145 non-standard CMOS types. The CMOS types are: 146 147 0 - Use the value of the physical CMOS 148 1 - 5 1/4 DD 149 2 - 5 1/4 HD 150 3 - 3 1/2 DD 151 4 - 3 1/2 HD 152 5 - 3 1/2 ED 153 6 - 3 1/2 ED 154 16 - unknown or not installed 155 156 (Note: there are two valid types for ED drives. This is because 5 was 157 initially chosen to represent floppy *tapes*, and 6 for ED drives. 158 AMI ignored this, and used 5 for ED drives. That's why the floppy 159 driver handles both.) 160 161 floppy=unexpected_interrupts 162 Print a warning message when an unexpected interrupt is received. 163 (default) 164 165 floppy=no_unexpected_interrupts 166 floppy=L40SX 167 Don't print a message when an unexpected interrupt is received. This 168 is needed on IBM L40SX laptops in certain video modes. (There seems 169 to be an interaction between video and floppy. The unexpected 170 interrupts affect only performance, and can be safely ignored.) 171 172 floppy=broken_dcl 173 Don't use the disk change line, but assume that the disk was 174 changed whenever the device node is reopened. Needed on some 175 boxes where the disk change line is broken or unsupported. 176 This should be regarded as a stopgap measure, indeed it makes 177 floppy operation less efficient due to unneeded cache 178 flushings, and slightly more unreliable. Please verify your 179 cable, connection and jumper settings if you have any DCL 180 problems. However, some older drives, and also some laptops 181 are known not to have a DCL. 182 183 floppy=debug 184 Print debugging messages. 185 186 floppy=messages 187 Print informational messages for some operations (disk change 188 notifications, warnings about over and underruns, and about 189 autodetection). 190 191 floppy=silent_dcl_clear 192 Uses a less noisy way to clear the disk change line (which 193 doesn't involve seeks). Implied by 'daring' option. 194 195 floppy=<nr>,irq 196 Sets the floppy IRQ to <nr> instead of 6. 197 198 floppy=<nr>,dma 199 Sets the floppy DMA channel to <nr> instead of 2. 200 201 floppy=slow 202 Use PS/2 stepping rate: 203 " PS/2 floppies have much slower step rates than regular floppies. 204 It's been recommended that take about 1/4 of the default speed 205 in some more extreme cases." 206 207 208 Supporting utilities and additional documentation: 209 ================================================== 210 211 Additional parameters of the floppy driver can be configured at 212 runtime. Utilities which do this can be found in the fdutils package. 213 This package also contains a new version of mtools which allows to 214 access high capacity disks (up to 1992K on a high density 3 1/2 disk!). 215 It also contains additional documentation about the floppy driver. 216 217 The latest version can be found at fdutils homepage: 218 http://fdutils.linux.lu 219 220 The fdutils releases can be found at: 221 http://fdutils.linux.lu/download.html 222 http://www.tux.org/pub/knaff/fdutils/ 223 ftp://metalab.unc.edu/pub/Linux/utils/disk-management/ 224 225 Reporting problems about the floppy driver 226 ========================================== 227 228 If you have a question or a bug report about the floppy driver, mail 229 me at Alain.Knaff@poboxes.com . If you post to Usenet, preferably use 230 comp.os.linux.hardware. As the volume in these groups is rather high, 231 be sure to include the word "floppy" (or "FLOPPY") in the subject 232 line. If the reported problem happens when mounting floppy disks, be 233 sure to mention also the type of the filesystem in the subject line. 234 235 Be sure to read the FAQ before mailing/posting any bug reports! 236 237 Alain 238 239 Changelog 240 ========= 241 242 10-30-2004 : Cleanup, updating, add reference to module configuration. 243 James Nelson <firstname.lastname@example.org> 244 245 6-3-2000 : Original Document