Michael Wu wrote:
On Wednesday 09 May 2007 19:12, Jeff Garzik wrote:John W. Linville wrote:+static inline void eeprom_93cx6_pulse_high(struct eeprom_93cx6 *eeprom) +{ + eeprom->reg_data_clock = 1; + eeprom->register_write(eeprom); + udelay(1); +} + +static inline void eeprom_93cx6_pulse_low(struct eeprom_93cx6 *eeprom) +{ + eeprom->reg_data_clock = 0; + eeprom->register_write(eeprom); + udelay(1); +}udelay-after-write normally indicates a PCI posting bug (or USB bus delay bug)Things may go bad if we try to bitbang the eeprom too fast.
You are misunderstanding the point here.I was not asking why you needed the delay. I was making an assertion about the unreliable nature of such delays.
Sending a register write to a device is vastly different from knowing that the write has been received and processed by the device.
On a PCI bus, this is called PCI write posting, where writes can be delayed and/or combined with other writes. There is a similar concept with USB, because you are dealing with packets going to and from a USB device.
You fundamentally cannot assume that the write has arrived at the device by the time the CPU is executing the next C statement (udelay) on the host.
The normal procedure for PCI is to issue a read, which thereby guarantees that any writes have been flushed to the device. I presume the same technique works with USB, but do not know for certain.
Yes, fully checked with sparse. No, it should not be __le32 because this keeps+static inline u8 rtl818x_ioread8(struct rtl8187_priv *priv, u8 *addr) +{ + u8 val; + + usb_control_msg(priv->udev, usb_rcvctrlpipe(priv->udev, 0), + RTL8187_REQ_GET_REG, RTL8187_REQT_READ, + (unsigned long)addr, 0, &val, sizeof(val), HZ / 2); + + return val; +} + +static inline u16 rtl818x_ioread16(struct rtl8187_priv *priv, __le16 *addr) +{ + __le16 val; + + usb_control_msg(priv->udev, usb_rcvctrlpipe(priv->udev, 0), + RTL8187_REQ_GET_REG, RTL8187_REQT_READ, + (unsigned long)addr, 0, &val, sizeof(val), HZ / 2); + + return le16_to_cpu(val); +} + +static inline u32 rtl818x_ioread32(struct rtl8187_priv *priv, __le32 *addr) +{ + __le32 val; + + usb_control_msg(priv->udev, usb_rcvctrlpipe(priv->udev, 0), + RTL8187_REQ_GET_REG, RTL8187_REQT_READ, + (unsigned long)addr, 0, &val, sizeof(val), HZ / 2); + + return le32_to_cpu(val); +}Return value should be __le32, etc. Was this driver checked with sparse?
Yes, you're right. I misread the code.
Most likely to just keep the hardware from choking or give the radio chip some time to receive the information.+void rtl8187_write_phy(struct ieee80211_hw *dev, u8 addr, u32 data) +{ + struct rtl8187_priv *priv = dev->priv; + + data <<= 8; + data |= addr | 0x80; + + rtl818x_iowrite8(priv, &priv->map->PHY[3], (data >> 24) & 0xFF); + rtl818x_iowrite8(priv, &priv->map->PHY[2], (data >> 16) & 0xFF); + rtl818x_iowrite8(priv, &priv->map->PHY[1], (data >> 8) & 0xFF); + rtl818x_iowrite8(priv, &priv->map->PHY[0], data & 0xFF); + + mdelay(1);unexplained delay -- write flush bug?
See above and reevaluate.
I have no idea what that does so I don't see the point in moving the number to some define. However, the hardware does seem to work okay without this part so I can remove it if you bothers you so much.+static int rtl8187_init_hw(struct ieee80211_hw *dev) +{ + struct rtl8187_priv *priv = dev->priv; + u8 reg; + int i; + + /* reset */ + rtl818x_iowrite8(priv, &priv->map->EEPROM_CMD, RTL818X_EEPROM_CMD_CONFIG); + reg = rtl818x_ioread8(priv, &priv->map->CONFIG3); + rtl818x_iowrite8(priv, &priv->map->CONFIG3, reg | RTL818X_CONFIG3_ANAPARAM_WRITE); + rtl818x_iowrite32(priv, &priv->map->ANAPARAM, RTL8225_ANAPARAM_ON); + rtl818x_iowrite32(priv, &priv->map->ANAPARAM2, RTL8225_ANAPARAM2_ON); + rtl818x_iowrite8(priv, &priv->map->CONFIG3, reg & ~RTL818X_CONFIG3_ANAPARAM_WRITE); + rtl818x_iowrite8(priv, &priv->map->EEPROM_CMD, RTL818X_EEPROM_CMD_NORMAL); + + rtl818x_iowrite16(priv, &priv->map->INT_MASK, 0); + + mdelay(200); + rtl818x_iowrite8(priv, (u8 *)0xFE18, 0x10); + rtl818x_iowrite8(priv, (u8 *)0xFE18, 0x11); + rtl818x_iowrite8(priv, (u8 *)0xFE18, 0x00); + mdelay(200);ditto also, kill the magic numbers
Regardless of any symbol issues, if it works without it, then remove it, because it is pointless code. All pointless code should be removed.
But nonetheless, for any "magic number" registers that remain, give them named constants that approximate their use as best as you can tell.
+ rtl818x_iowrite16(priv, &priv->map->BRSR, 0x01F3); + reg = rtl818x_ioread16(priv, &priv->map->PGSELECT) & 0xfffe; + rtl818x_iowrite16(priv, &priv->map->PGSELECT, reg | 0x1); + rtl818x_iowrite16(priv, (__le16 *)0xFFFE, 0x10); + rtl818x_iowrite8(priv, &priv->map->TALLY_SEL, 0x80); + rtl818x_iowrite8(priv, (u8 *)0xFFFF, 0x60); + rtl818x_iowrite16(priv, &priv->map->PGSELECT, reg);this entire function can run for a very long time, without schedulingAll the mdelays can be converted to msleep AFAICT.
You still need to address write posting.
This seems an invalid use of skb->cb. Don't use skb->cb.The driver owns these rx skbs, so it owns skb->cb. Why not?
Wrong. It no longer owns the skbs once it passes them to the stack.
+static void rtl8187_register_write(struct eeprom_93cx6 *eeprom) +{ + struct ieee80211_hw *dev = eeprom->data; + struct rtl8187_priv *priv = dev->priv; + u8 reg = RTL818X_EEPROM_CMD_PROGRAM; + + if (eeprom->reg_data_in) + reg |= RTL818X_EEPROM_CMD_WRITE; + if (eeprom->reg_data_out) + reg |= RTL818X_EEPROM_CMD_READ; + if (eeprom->reg_data_clock) + reg |= RTL818X_EEPROM_CMD_CK; + if (eeprom->reg_chip_select) + reg |= RTL818X_EEPROM_CMD_CS; + + rtl818x_iowrite8(priv, &priv->map->EEPROM_CMD, reg); + udelay(10);questionable delayMost likely to prevent hitting the eeprom too fast.
see above, RE write posting
They're not about being accurate as they are about giving the hardware enough time to adjust. I suspect a number of them are arbitrary, but there's also many necessary ones.+ eeprom.data = dev; + eeprom.register_read = rtl8187_register_read; + eeprom.register_write = rtl8187_register_write; + if (rtl818x_ioread32(priv, &priv->map->RX_CONF) & (1 << 6)) + eeprom.width = PCI_EEPROM_WIDTH_93C66; + else + eeprom.width = PCI_EEPROM_WIDTH_93C46; + + rtl818x_iowrite8(priv, &priv->map->EEPROM_CMD, RTL818X_EEPROM_CMD_CONFIG); + udelay(10);ditto+ * Radio tuning for RTL8225 on RTL8187this file is full of questionable delays -- these sorts of things tend to not be as accurate as you think, across all platforms, due to PCI posting and/or USB bus delays
see above. You have no guarantee from platform to platform that each delay will actually delay for the requested amount of time, if you see that operations are actually occurring in parallel.
This is also only called at open time. I suspect most of the delays which are 100 ms and over can be reduced if you wish. I haven't had time to figure out which delays are really necessary. Converting everything to msleep is also probably fine.+void rtl8225z2_rf_init(struct ieee80211_hw *dev) +{ + struct rtl8187_priv *priv = dev->priv; + int i; + + rtl8225_write(dev, 0x0, 0x2BF); mdelay(1); + rtl8225_write(dev, 0x1, 0xEE0); mdelay(1); + rtl8225_write(dev, 0x2, 0x44D); mdelay(1); + rtl8225_write(dev, 0x3, 0x441); mdelay(1); + rtl8225_write(dev, 0x4, 0x8C3); mdelay(1); + rtl8225_write(dev, 0x5, 0xC72); mdelay(1); + rtl8225_write(dev, 0x6, 0x0E6); mdelay(1); + rtl8225_write(dev, 0x7, 0x82A); mdelay(1); + rtl8225_write(dev, 0x8, 0x03F); mdelay(1); + rtl8225_write(dev, 0x9, 0x335); mdelay(1); + rtl8225_write(dev, 0xa, 0x9D4); mdelay(1); + rtl8225_write(dev, 0xb, 0x7BB); mdelay(1); + rtl8225_write(dev, 0xc, 0x850); mdelay(1); + rtl8225_write(dev, 0xd, 0xCDF); mdelay(1); + rtl8225_write(dev, 0xe, 0x02B); mdelay(1); + rtl8225_write(dev, 0xf, 0x114); mdelay(100); + + rtl8225_write(dev, 0x0, 0x1B7); + + for (i = 0; i < ARRAY_SIZE(rtl8225z2_rxgain); i++) { + rtl8225_write(dev, 0x1, i + 1); + rtl8225_write(dev, 0x2, rtl8225z2_rxgain[i]); + } + + rtl8225_write(dev, 0x3, 0x080); + rtl8225_write(dev, 0x5, 0x004); + rtl8225_write(dev, 0x0, 0x0B7); + rtl8225_write(dev, 0x2, 0xc4D); + + mdelay(200); + rtl8225_write(dev, 0x2, 0x44D); + mdelay(100); + + if (!(rtl8225_read(dev, 6) & (1 << 7))) { + rtl8225_write(dev, 0x02, 0x0C4D); + mdelay(200); + rtl8225_write(dev, 0x02, 0x044D); + mdelay(100); + if (!(rtl8225_read(dev, 6) & (1 << 7))) + printk(KERN_WARNING "%s: RF Calibration Failed! %x\n", + wiphy_name(dev->wiphy), rtl8225_read(dev, 6)); + } + + mdelay(200); + + rtl8225_write(dev, 0x0, 0x2BF); + + for (i = 0; i < ARRAY_SIZE(rtl8225_agc); i++) { + rtl8225_write_phy_ofdm(dev, 0xB, rtl8225_agc[i]); + mdelay(1); + rtl8225_write_phy_ofdm(dev, 0xA, 0x80 + i); + mdelay(1); + } + + mdelay(1); + + rtl8225_write_phy_ofdm(dev, 0x00, 0x01); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x01, 0x02); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x02, 0x42); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x03, 0x00); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x04, 0x00); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x05, 0x00); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x06, 0x40); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x07, 0x00); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x08, 0x40); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x09, 0xfe); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x0a, 0x08); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x0b, 0x80); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x0c, 0x01); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x0d, 0x43); + rtl8225_write_phy_ofdm(dev, 0x0e, 0xd3); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x0f, 0x38); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x10, 0x84); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x11, 0x07); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x12, 0x20); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x13, 0x20); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x14, 0x00); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x15, 0x40); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x16, 0x00); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x17, 0x40); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x18, 0xef); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x19, 0x19); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x1a, 0x20); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x1b, 0x15); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x1c, 0x04); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x1d, 0xc5); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x1e, 0x95); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x1f, 0x75); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x20, 0x1f); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x21, 0x17); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x22, 0x16); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x23, 0x80); mdelay(1); //FIXME: not needed? + rtl8225_write_phy_ofdm(dev, 0x24, 0x46); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x25, 0x00); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x26, 0x90); mdelay(1); + rtl8225_write_phy_ofdm(dev, 0x27, 0x88); mdelay(1); + + rtl8225_write_phy_ofdm(dev, 0x0b, rtl8225z2_gain_bg[4 * 3]); + rtl8225_write_phy_ofdm(dev, 0x1b, rtl8225z2_gain_bg[4 * 3 + 1]); + rtl8225_write_phy_ofdm(dev, 0x1d, rtl8225z2_gain_bg[4 * 3 + 2]); + rtl8225_write_phy_ofdm(dev, 0x21, 0x37); + + rtl8225_write_phy_cck(dev, 0x00, 0x98); mdelay(1); + rtl8225_write_phy_cck(dev, 0x03, 0x20); mdelay(1); + rtl8225_write_phy_cck(dev, 0x04, 0x7e); mdelay(1); + rtl8225_write_phy_cck(dev, 0x05, 0x12); mdelay(1); + rtl8225_write_phy_cck(dev, 0x06, 0xfc); mdelay(1); + rtl8225_write_phy_cck(dev, 0x07, 0x78); mdelay(1); + rtl8225_write_phy_cck(dev, 0x08, 0x2e); mdelay(1); + rtl8225_write_phy_cck(dev, 0x10, 0x9b); mdelay(1); + rtl8225_write_phy_cck(dev, 0x11, 0x88); mdelay(1); + rtl8225_write_phy_cck(dev, 0x12, 0x47); mdelay(1); + rtl8225_write_phy_cck(dev, 0x13, 0xd0); + rtl8225_write_phy_cck(dev, 0x19, 0x00); + rtl8225_write_phy_cck(dev, 0x1a, 0xa0); + rtl8225_write_phy_cck(dev, 0x1b, 0x08); + rtl8225_write_phy_cck(dev, 0x40, 0x86); + rtl8225_write_phy_cck(dev, 0x41, 0x8d); mdelay(1); + rtl8225_write_phy_cck(dev, 0x42, 0x15); mdelay(1); + rtl8225_write_phy_cck(dev, 0x43, 0x18); mdelay(1); + rtl8225_write_phy_cck(dev, 0x44, 0x36); mdelay(1); + rtl8225_write_phy_cck(dev, 0x45, 0x35); mdelay(1); + rtl8225_write_phy_cck(dev, 0x46, 0x2e); mdelay(1); + rtl8225_write_phy_cck(dev, 0x47, 0x25); mdelay(1); + rtl8225_write_phy_cck(dev, 0x48, 0x1c); mdelay(1); + rtl8225_write_phy_cck(dev, 0x49, 0x12); mdelay(1); + rtl8225_write_phy_cck(dev, 0x4a, 0x09); mdelay(1); + rtl8225_write_phy_cck(dev, 0x4b, 0x04); mdelay(1); + rtl8225_write_phy_cck(dev, 0x4c, 0x05); mdelay(1); + + rtl818x_iowrite8(priv, (u8 *)0xFF5B, 0x0D); mdelay(1); + + rtl8225z2_rf_set_tx_power(dev, 1); + + /* RX antenna default to A */ + rtl8225_write_phy_cck(dev, 0x10, 0x9b); mdelay(1); /* B: 0xDB */ + rtl8225_write_phy_ofdm(dev, 0x26, 0x90); mdelay(1); /* B: 0x10 */ + + rtl818x_iowrite8(priv, &priv->map->TX_ANTENNA, 0x03); /* B: 0x00 */ + mdelay(1); + rtl818x_iowrite32(priv, (__le32 *)0xFF94, 0x3dc00002);completely insane, unacceptable amount of "freezing the kernel" in mdelay()
msleep() will definitely solve the "freezing kernel for way too long" problem.
But not the write posting considerations.
+++ b/drivers/net/wireless/rtl818x.h @@ -0,0 +1,212 @@ +#ifndef RTL818X_H +#define RTL818X_H + +struct rtl818x_csr { + u8 MAC[6]; + u8 reserved_0[2]; + __le32 MAR[2]; + u8 RX_FIFO_COUNT; + u8 reserved_1; + u8 TX_FIFO_COUNT; + u8 BQREQ; + u8 reserved_2[4]; + __le32 TSFT[2]; + __le32 TLPDA; + __le32 TNPDA; + __le32 THPDA; + __le16 BRSR; + u8 BSSID[6]; + u8 RESP_RATE; + u8 EIFS; + u8 reserved_3[1]; + u8 CMD; +#define RTL818X_CMD_TX_ENABLE (1 << 2) +#define RTL818X_CMD_RX_ENABLE (1 << 3) +#define RTL818X_CMD_RESET (1 << 4) + u8 reserved_4[4]; + __le16 INT_MASK; + __le16 INT_STATUS; +#define RTL818X_INT_RX_OK (1 << 0) +#define RTL818X_INT_RX_ERR (1 << 1) +#define RTL818X_INT_TXL_OK (1 << 2) +#define RTL818X_INT_TXL_ERR (1 << 3) +#define RTL818X_INT_RX_DU (1 << 4) +#define RTL818X_INT_RX_FO (1 << 5) +#define RTL818X_INT_TXN_OK (1 << 6) +#define RTL818X_INT_TXN_ERR (1 << 7) +#define RTL818X_INT_TXH_OK (1 << 8) +#define RTL818X_INT_TXH_ERR (1 << 9) +#define RTL818X_INT_TXB_OK (1 << 10) +#define RTL818X_INT_TXB_ERR (1 << 11) +#define RTL818X_INT_ATIM (1 << 12) +#define RTL818X_INT_BEACON (1 << 13) +#define RTL818X_INT_TIME_OUT (1 << 14) +#define RTL818X_INT_TX_FO (1 << 15) + __le32 TX_CONF; +#define RTL818X_TX_CONF_LOOPBACK_MAC (1 << 17) +#define RTL818X_TX_CONF_NO_ICV (1 << 19) +#define RTL818X_TX_CONF_DISCW (1 << 20) +#define RTL818X_TX_CONF_R8180_ABCD (2 << 25) +#define RTL818X_TX_CONF_R8180_F (3 << 25) +#define RTL818X_TX_CONF_R8185_ABC (4 << 25) +#define RTL818X_TX_CONF_R8185_D (5 << 25) +#define RTL818X_TX_CONF_HWVER_MASK (7 << 25) +#define RTL818X_TX_CONF_CW_MIN (1 << 31) + __le32 RX_CONF; +#define RTL818X_RX_CONF_MONITOR (1 << 0) +#define RTL818X_RX_CONF_NICMAC (1 << 1) +#define RTL818X_RX_CONF_MULTICAST (1 << 2) +#define RTL818X_RX_CONF_BROADCAST (1 << 3) +#define RTL818X_RX_CONF_DATA (1 << 18) +#define RTL818X_RX_CONF_CTRL (1 << 19) +#define RTL818X_RX_CONF_MGMT (1 << 20) +#define RTL818X_RX_CONF_BSSID (1 << 23) +#define RTL818X_RX_CONF_RX_AUTORESETPHY (1 << 28) +#define RTL818X_RX_CONF_ONLYERLPKT (1 << 31) + __le32 INT_TIMEOUT; + __le32 TBDA; + u8 EEPROM_CMD; +#define RTL818X_EEPROM_CMD_READ (1 << 0) +#define RTL818X_EEPROM_CMD_WRITE (1 << 1) +#define RTL818X_EEPROM_CMD_CK (1 << 2) +#define RTL818X_EEPROM_CMD_CS (1 << 3) +#define RTL818X_EEPROM_CMD_NORMAL (0 << 6) +#define RTL818X_EEPROM_CMD_LOAD (1 << 6) +#define RTL818X_EEPROM_CMD_PROGRAM (2 << 6) +#define RTL818X_EEPROM_CMD_CONFIG (3 << 6) + u8 CONFIG0; + u8 CONFIG1; + u8 CONFIG2; + __le32 ANAPARAM; + u8 MSR; +#define RTL818X_MSR_NO_LINK (0 << 2) +#define RTL818X_MSR_ADHOC (1 << 2) +#define RTL818X_MSR_INFRA (2 << 2) + u8 CONFIG3; +#define RTL818X_CONFIG3_ANAPARAM_WRITE (1 << 6) + u8 CONFIG4; +#define RTL818X_CONFIG4_POWEROFF (1 << 6) +#define RTL818X_CONFIG4_VCOOFF (1 << 7) + u8 TESTR; + u8 reserved_9[2]; + __le16 PGSELECT; + __le32 ANAPARAM2; + u8 reserved_10[12]; + __le16 BEACON_INTERVAL; + __le16 ATIM_WND; + __le16 BEACON_INTERVAL_TIME; + __le16 ATIMTR_INTERVAL; + u8 reserved_11[4]; + u8 PHY[4]; + __le16 RFPinsOutput; + __le16 RFPinsEnable; + __le16 RFPinsSelect; + __le16 RFPinsInput; + __le32 RF_PARA; + __le32 RF_TIMING; + u8 GP_ENABLE; + u8 GPIO; + u8 reserved_12[10]; + u8 TX_AGC_CTL; +#define RTL818X_TX_AGC_CTL_PERPACKET_GAIN_SHIFT (1 << 0) +#define RTL818X_TX_AGC_CTL_PERPACKET_ANTSEL_SHIFT (1 << 1) +#define RTL818X_TX_AGC_CTL_FEEDBACK_ANT (1 << 2) + u8 TX_GAIN_CCK; + u8 TX_GAIN_OFDM; + u8 TX_ANTENNA; + u8 reserved_13[16]; + u8 WPA_CONF; + u8 reserved_14[3]; + u8 SIFS; + u8 DIFS; + u8 SLOT; + u8 reserved_15[5]; + u8 CW_CONF; +#define RTL818X_CW_CONF_PERPACKET_CW_SHIFT (1 << 0) +#define RTL818X_CW_CONF_PERPACKET_RETRY_SHIFT (1 << 1) + u8 CW_VAL; + u8 RATE_FALLBACK; + u8 reserved_16[25]; + u8 CONFIG5; + u8 TX_DMA_POLLING; + u8 reserved_17[2]; + __le16 CWR; + u8 RETRY_CTR; + u8 reserved_18[5]; + __le32 RDSAR; + u8 reserved_19[18]; + u16 TALLY_CNT; + u8 TALLY_SEL; +} __attribute__((packed));enums have more visibility to the compiler and debugging toolsenums don't have the same kind of typechecking this has.
You're right. They actually HAVE typechecking, whereas cpp #defines do not.
We like typechecking in Linux, but your #defines have none. Jeff - To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
