RPI BCM2708 Parameters

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module: sdhci-bcm2708

Support for SDHCI device on BCM2708. SDHCI platform device - Arasan SD controller in ​BCM2708

module parameter description purpose / reason to use
allow_highspeed Allow high speed transfers modes Parameter to disable high-speed mode for the few cards that still might have problems. High-speed mode is enabled by default.[1][2]
emmc_clock_freq Specify the speed of emmc clock 25 MHz or 50 MHz (high speed mode). 50 MHz (default) clock is perfect to drive the SD interface at ideal frequencies[3][4]
sync_after_dma Block in driver until dma complete We get CRC and DEND errors unless we wait for he SD controller to finish reading/writing to the card[5][6]


missing_status Use the missing status quirk May improve interrupt latency on some sdcards [8]
spurious_crc_acmd51 Use the spurious crc quirk for reading SCR (ACMD51) unknown
enable_llm Enable low-latency mode Low latency mode for sdcards (1=enable)[9][10]
extra_messages Enable more sdcard warning messages

module: dwc_otg

HS OTG USB Controller driver

module parameter description purpose / reason to use
fiq_fix_enable Enable/disable FIQ patch Lower number of interrupts when USB is idle, gains about 10% performance on the ARM side[11]


speed Limit speed to full speed set to 1 to limit to full speed (USB 1.1) (When set to 0: USB 2.0 high speed) Might break some keyboards? [13]
lpm_enable Change USB Link Power Management Default is 0 to disable LPM support [14]
microframe_schedule Enable/disable microframe scheduler Improve USB with multiple endpoints? Default is on (1)[15]
nak_holdoff_enable Enable the NACK holdoff Reduce interrupt overhead when devices hold off using NACKs[16]

module: i2c-bcm2708

BSC controller driver for Broadcom BCM2708

module parameter description purpose / reason to use
baudrate The I2C baudrate Change default (100KHz) baudrate for i2c [17] [18]

module: w1-gpio

GPIO w1 bus master driver

module parameter description purpose / reason to use
pullup - Enable pullup to enable parasite power in bitbang mode [19]


  1. https://github.com/raspberrypi/linux/commit/fdc3114aea4a8c869fb3478b1b2563bf595dcb6c
  2. http://www.raspberrypi.org/phpBB3/viewtopic.php?p=91559#p96480
  3. https://github.com/raspberrypi/linux/commit/819cbdd1d18f150070257737b0b20de6536eac48
  4. https://github.com/raspberrypi/linux/commit/4144c02c7b8e4f9c3d3a5be8d33d05da98a01bee
  5. https://github.com/raspberrypi/firmware/issues/19#issuecomment-7442015
  6. https://github.com/raspberrypi/linux/commit/53011c10f7477d80dbae40b1be6dfad150e6c7eb
  7. https://github.com/raspberrypi/linux/commit/8e39b3019b3494305d87b7489820178580369eb7
  8. https://github.com/raspberrypi/linux/pull/72
  9. https://github.com/raspberrypi/linux/pull/72#issuecomment-8066275
  10. https://github.com/raspberrypi/linux/commit/77f82f9de9f88fc7ff693497dcb6b0ef5b1c5e63#diff-8af9a46d1b0e50638bf61a18ad2d09b7R1401
  11. https://github.com/raspberrypi/linux/commit/1f45d3d733d51369b3e21b3152839e24a840ec59
  12. http://www.raspberrypi.org/phpBB3/viewtopic.php?f=28&t=7866&start=75
  13. http://raspberrypi.stackexchange.com/questions/4090/how-can-dwc-otg-speed-1-be-made-to-work
  14. https://github.com/raspberrypi/linux/commit/9025bc52c25cf7526ef8b204e9a6dbd620d31529#diff-b1c763eb039590f135f0fd3b01dc42b3
  15. https://github.com/raspberrypi/linux/commit/5cc98c1e75700e51e4a31d8a05b4a55a7d29648c
  16. https://github.com/raspberrypi/linux/commit/9e07cbc724ea3c094a8ea764a093335e5f42f088
  17. http://www.raspberrypi.org/phpBB3/viewtopic.php?p=342126&sid=c0235b5b385e7d0104399f194616d59f#p342126
  18. https://github.com/raspberrypi/linux/commit/e5c5956ed7aa509187515a1acfe4ec2ca6d63433
  19. https://github.com/raspberrypi/linux/commit/36a1ff9b3debcd596f531feaeb0ee92879cba31c