1This file describes the floppy driver. 2 3FAQ list: 4========= 5 6 A FAQ list may be found in the fdutils package (see below), and also 7at http://fdutils.linux.lu/FAQ.html 8 9 10LILO configuration options (Thinkpad users, read this) 11====================================================== 12 13 The floppy driver is configured using the 'floppy=' option in 14lilo. This option can be typed at the boot prompt, or entered in the 15lilo configuration file. 16 Example: If your kernel is called linux-2.2.13, type the following line 17at the lilo boot prompt (if you have a thinkpad): 18 linux-2.2.13 floppy=thinkpad 19You may also enter the following line in /etc/lilo.conf, in the description 20of linux-2.2.13: 21 append = "floppy=thinkpad" 22 23 Several floppy related options may be given, example: 24 linux-2.2.13 floppy=daring floppy=two_fdc 25 append = "floppy=daring floppy=two_fdc" 26 27 If you give options both in the lilo config file and on the boot 28prompt, the option strings of both places are concatenated, the boot 29prompt options coming last. That's why there are also options to 30restore the default behavior. 31 32 If you use the floppy driver as a module, use the following syntax: 33 insmod floppy <options> 34 35Example: 36 insmod floppy daring two_fdc 37 38 Some versions of insmod are buggy in one way or another. If you have 39any problems (options not being passed correctly, segfaults during 40insmod), first check whether there is a more recent version. 41 42 The floppy related options include: 43 44 floppy=asus_pci 45 Sets the bit mask to allow only units 0 and 1. (default) 46 47 floppy=daring 48 Tells the floppy driver that you have a well behaved floppy controller. 49 This allows more efficient and smoother operation, but may fail on 50 certain controllers. This may speed up certain operations. 51 52 floppy=0,daring 53 Tells the floppy driver that your floppy controller should be used 54 with caution. 55 56 floppy=one_fdc 57 Tells the floppy driver that you have only one floppy controller. 58 (default) 59 60 floppy=two_fdc 61 floppy=<address>,two_fdc 62 Tells the floppy driver that you have two floppy controllers. 63 The second floppy controller is assumed to be at <address>. 64 This option is not needed if the second controller is at address 65 0x370, and if you use the 'cmos' option. 66 67 floppy=thinkpad 68 Tells the floppy driver that you have a Thinkpad. Thinkpads use an 69 inverted convention for the disk change line. 70 71 floppy=0,thinkpad 72 Tells the floppy driver that you don't have a Thinkpad. 73 74 floppy=omnibook 75 floppy=nodma 76 Tells the floppy driver not to use Dma for data transfers. 77 This is needed on HP Omnibooks, which don't have a workable 78 DMA channel for the floppy driver. This option is also useful 79 if you frequently get "Unable to allocate DMA memory" messages. 80 Indeed, dma memory needs to be continuous in physical memory, 81 and is thus harder to find, whereas non-dma buffers may be 82 allocated in virtual memory. However, I advise against this if 83 you have an FDC without a FIFO (8272A or 82072). 82072A and 84 later are OK. You also need at least a 486 to use nodma. 85 If you use nodma mode, I suggest you also set the FIFO 86 threshold to 10 or lower, in order to limit the number of data 87 transfer interrupts. 88 89 If you have a FIFO-able FDC, the floppy driver automatically 90 falls back on non DMA mode if no DMA-able memory can be found. 91 If you want to avoid this, explicitly ask for 'yesdma'. 92 93 floppy=yesdma 94 Tells the floppy driver that a workable DMA channel is available. 95 (default) 96 97 floppy=nofifo 98 Disables the FIFO entirely. This is needed if you get "Bus 99 master arbitration error" messages from your Ethernet card (or 100 from other devices) while accessing the floppy. 101 102 floppy=fifo 103 Enables the FIFO. (default) 104 105 floppy=<threshold>,fifo_depth 106 Sets the FIFO threshold. This is mostly relevant in DMA 107 mode. If this is higher, the floppy driver tolerates more 108 interrupt latency, but it triggers more interrupts (i.e. it 109 imposes more load on the rest of the system). If this is 110 lower, the interrupt latency should be lower too (faster 111 processor). The benefit of a lower threshold is less 112 interrupts. 113 To tune the fifo threshold, switch on over/underrun messages 114 using 'floppycontrol --messages'. Then access a floppy 115 disk. If you get a huge amount of "Over/Underrun - retrying" 116 messages, then the fifo threshold is too low. Try with a 117 higher value, until you only get an occasional Over/Underrun. 118 It is a good idea to compile the floppy driver as a module 119 when doing this tuning. Indeed, it allows to try different 120 fifo values without rebooting the machine for each test. Note 121 that you need to do 'floppycontrol --messages' every time you 122 re-insert the module. 123 Usually, tuning the fifo threshold should not be needed, as 124 the default (0xa) is reasonable. 125 126 floppy=<drive>,<type>,cmos 127 Sets the CMOS type of <drive> to <type>. This is mandatory if 128 you have more than two floppy drives (only two can be 129 described in the physical CMOS), or if your BIOS uses 130 non-standard CMOS types. The CMOS types are: 131 0 - Use the value of the physical CMOS 132 1 - 5 1/4 DD 133 2 - 5 1/4 HD 134 3 - 3 1/2 DD 135 4 - 3 1/2 HD 136 5 - 3 1/2 ED 137 6 - 3 1/2 ED 138 16 - unknown or not installed 139 (Note: there are two valid types for ED drives. This is because 5 was 140 initially chosen to represent floppy *tapes*, and 6 for ED drives. 141 AMI ignored this, and used 5 for ED drives. That's why the floppy 142 driver handles both.) 143 144 floppy=unexpected_interrupts 145 Print a warning message when an unexpected interrupt is received. 146 (default) 147 148 floppy=no_unexpected_interrupts 149 floppy=L40SX 150 Don't print a message when an unexpected interrupt is received. This 151 is needed on IBM L40SX laptops in certain video modes. (There seems 152 to be an interaction between video and floppy. The unexpected 153 interrupts affect only performance, and can be safely ignored.) 154 155 floppy=broken_dcl 156 Don't use the disk change line, but assume that the disk was 157 changed whenever the device node is reopened. Needed on some 158 boxes where the disk change line is broken or unsupported. 159 This should be regarded as a stopgap measure, indeed it makes 160 floppy operation less efficient due to unneeded cache 161 flushings, and slightly more unreliable. Please verify your 162 cable, connection and jumper settings if you have any DCL 163 problems. However, some older drives, and also some laptops 164 are known not to have a DCL. 165 166 floppy=debug 167 Print debugging messages. 168 169 floppy=messages 170 Print informational messages for some operations (disk change 171 notifications, warnings about over and underruns, and about 172 autodetection). 173 174 floppy=silent_dcl_clear 175 Uses a less noisy way to clear the disk change line (which 176 doesn't involve seeks). Implied by 'daring' option. 177 178 floppy=<nr>,irq 179 Sets the floppy IRQ to <nr> instead of 6. 180 181 floppy=<nr>,dma 182 Sets the floppy DMA channel to <nr> instead of 2. 183 184 floppy=slow 185 Use PS/2 stepping rate: 186 " PS/2 floppies have much slower step rates than regular floppies. 187 It's been recommended that take about 1/4 of the default speed 188 in some more extreme cases." 189 190 191 192Supporting utilities and additional documentation: 193================================================== 194 195 Additional parameters of the floppy driver can be configured at 196runtime. Utilities which do this can be found in the fdutils package. 197This package also contains a new version of mtools which allows to 198access high capacity disks (up to 1992K on a high density 3 1/2 disk!). 199It also contains additional documentation about the floppy driver. 200 201The latest version can be found at fdutils homepage: 202 http://fdutils.linux.lu 203 204The fdutils-5.4 release can be found at: 205 http://fdutils.linux.lu/fdutils-5.4.src.tar.gz 206 http://www.tux.org/pub/knaff/fdutils/fdutils-5.4.src.tar.gz 207 ftp://metalab.unc.edu/pub/Linux/utils/disk-management/fdutils-5.4.src.tar.gz 208 209Reporting problems about the floppy driver 210========================================== 211 212 If you have a question or a bug report about the floppy driver, mail 213me at Alain.Knaff@poboxes.com . If you post to Usenet, preferably use 214comp.os.linux.hardware. As the volume in these groups is rather high, 215be sure to include the word "floppy" (or "FLOPPY") in the subject 216line. If the reported problem happens when mounting floppy disks, be 217sure to mention also the type of the filesystem in the subject line. 218 219 Be sure to read the FAQ before mailing/posting any bug reports! 220 221 Alain 222