Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755686AbZCMHle (ORCPT ); Fri, 13 Mar 2009 03:41:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751678AbZCMHlY (ORCPT ); Fri, 13 Mar 2009 03:41:24 -0400 Received: from mail.gmx.net ([213.165.64.20]:33796 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750970AbZCMHlW (ORCPT ); Fri, 13 Mar 2009 03:41:22 -0400 X-Authenticated: #20450766 X-Provags-ID: V01U2FsdGVkX1+UlpJbFSuUTjnDnTwF9+PwO1MSYCiKn8qLuj7g+C 8TiZA/NKeQgeb1 Date: Fri, 13 Mar 2009 08:41:23 +0100 (CET) From: Guennadi Liakhovetski X-X-Sender: lyakh@axis700.grange To: Dan Williams cc: linux-kernel@vger.kernel.org Subject: [PATCH] ipu_idmac: code clean-up and robustness improvements Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Y-GMX-Trusted: 0 X-FuHaFi: 0.42 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 20427 Lines: 620 General code clean-up: remove superfluous semicolons, update comments. Robustness improvements: add DMA error handling to the ISR, move common code fragments to functions, fix scatter-gather element queuing in the ISR, survive channel freeing and re-allocation in a quick succession. Signed-off-by: Guennadi Liakhovetski --- Dan, I've been using this patch for a while, without any need for a change, so, it should be fine to go upstream. drivers/dma/ipu/ipu_idmac.c | 300 ++++++++++++++++++++++++++++--------------- 1 files changed, 196 insertions(+), 104 deletions(-) diff --git a/drivers/dma/ipu/ipu_idmac.c b/drivers/dma/ipu/ipu_idmac.c index 1f154d0..91e6e4e 100644 --- a/drivers/dma/ipu/ipu_idmac.c +++ b/drivers/dma/ipu/ipu_idmac.c @@ -28,6 +28,9 @@ #define FS_VF_IN_VALID 0x00000002 #define FS_ENC_IN_VALID 0x00000001 +static int ipu_disable_channel(struct idmac *idmac, struct idmac_channel *ichan, + bool wait_for_stop); + /* * There can be only one, we could allocate it dynamically, but then we'd have * to add an extra parameter to some functions, and use something as ugly as @@ -107,7 +110,7 @@ static uint32_t bytes_per_pixel(enum pixel_fmt fmt) } } -/* Enable / disable direct write to memory by the Camera Sensor Interface */ +/* Enable direct write to memory by the Camera Sensor Interface */ static void ipu_ic_enable_task(struct ipu *ipu, enum ipu_channel channel) { uint32_t ic_conf, mask; @@ -126,6 +129,7 @@ static void ipu_ic_enable_task(struct ipu *ipu, enum ipu_channel channel) idmac_write_icreg(ipu, ic_conf, IC_CONF); } +/* Called under spin_lock_irqsave(&ipu_data.lock) */ static void ipu_ic_disable_task(struct ipu *ipu, enum ipu_channel channel) { uint32_t ic_conf, mask; @@ -422,7 +426,7 @@ static void ipu_ch_param_set_size(union chan_param_mem *params, break; default: dev_err(ipu_data.dev, - "mxc ipu: unimplemented pixel format %d\n", pixel_fmt); + "mx3 ipu: unimplemented pixel format %d\n", pixel_fmt); break; } @@ -433,20 +437,20 @@ static void ipu_ch_param_set_burst_size(union chan_param_mem *params, uint16_t burst_pixels) { params->pp.npb = burst_pixels - 1; -}; +} static void ipu_ch_param_set_buffer(union chan_param_mem *params, dma_addr_t buf0, dma_addr_t buf1) { params->pp.eba0 = buf0; params->pp.eba1 = buf1; -}; +} static void ipu_ch_param_set_rotation(union chan_param_mem *params, enum ipu_rotate_mode rotate) { params->pp.bam = rotate; -}; +} static void ipu_write_param_mem(uint32_t addr, uint32_t *data, uint32_t num_words) @@ -571,7 +575,7 @@ static uint32_t dma_param_addr(uint32_t dma_ch) { /* Channel Parameter Memory */ return 0x10000 | (dma_ch << 4); -}; +} static void ipu_channel_set_priority(struct ipu *ipu, enum ipu_channel channel, bool prio) @@ -611,7 +615,8 @@ static uint32_t ipu_channel_conf_mask(enum ipu_channel channel) /** * ipu_enable_channel() - enable an IPU channel. - * @channel: channel ID. + * @idmac: IPU DMAC context. + * @ichan: IDMAC channel. * @return: 0 on success or negative error code on failure. */ static int ipu_enable_channel(struct idmac *idmac, struct idmac_channel *ichan) @@ -649,7 +654,7 @@ static int ipu_enable_channel(struct idmac *idmac, struct idmac_channel *ichan) /** * ipu_init_channel_buffer() - initialize a buffer for logical IPU channel. - * @channel: channel ID. + * @ichan: IDMAC channel. * @pixel_fmt: pixel format of buffer. Pixel format is a FOURCC ASCII code. * @width: width of buffer in pixels. * @height: height of buffer in pixels. @@ -687,7 +692,7 @@ static int ipu_init_channel_buffer(struct idmac_channel *ichan, } /* IC channel's stride must be a multiple of 8 pixels */ - if ((channel <= 13) && (stride % 8)) { + if ((channel <= IDMAC_IC_13) && (stride % 8)) { dev_err(ipu->dev, "Stride must be 8 pixel multiple\n"); return -EINVAL; } @@ -752,7 +757,7 @@ static void ipu_select_buffer(enum ipu_channel channel, int buffer_n) /** * ipu_update_channel_buffer() - update physical address of a channel buffer. - * @channel: channel ID. + * @ichan: IDMAC channel. * @buffer_n: buffer number to update. * 0 or 1 are the only valid values. * @phyaddr: buffer physical address. @@ -760,9 +765,10 @@ static void ipu_select_buffer(enum ipu_channel channel, int buffer_n) * function will fail if the buffer is set to ready. */ /* Called under spin_lock(_irqsave)(&ichan->lock) */ -static int ipu_update_channel_buffer(enum ipu_channel channel, +static int ipu_update_channel_buffer(struct idmac_channel *ichan, int buffer_n, dma_addr_t phyaddr) { + enum ipu_channel channel = ichan->dma_chan.chan_id; uint32_t reg; unsigned long flags; @@ -771,8 +777,8 @@ static int ipu_update_channel_buffer(enum ipu_channel channel, if (buffer_n == 0) { reg = idmac_read_ipureg(&ipu_data, IPU_CHA_BUF0_RDY); if (reg & (1UL << channel)) { - spin_unlock_irqrestore(&ipu_data.lock, flags); - return -EACCES; + ipu_ic_disable_task(&ipu_data, channel); + ichan->status = IPU_CHANNEL_READY; } /* 44.3.3.1.9 - Row Number 1 (WORD1, offset 0) */ @@ -782,8 +788,8 @@ static int ipu_update_channel_buffer(enum ipu_channel channel, } else { reg = idmac_read_ipureg(&ipu_data, IPU_CHA_BUF1_RDY); if (reg & (1UL << channel)) { - spin_unlock_irqrestore(&ipu_data.lock, flags); - return -EACCES; + ipu_ic_disable_task(&ipu_data, channel); + ichan->status = IPU_CHANNEL_READY; } /* Check if double-buffering is already enabled */ @@ -805,6 +811,39 @@ static int ipu_update_channel_buffer(enum ipu_channel channel, } /* Called under spin_lock_irqsave(&ichan->lock) */ +static int ipu_submit_buffer(struct idmac_channel *ichan, + struct idmac_tx_desc *desc, struct scatterlist *sg, int buf_idx) +{ + unsigned int chan_id = ichan->dma_chan.chan_id; + struct device *dev = &ichan->dma_chan.dev->device; + int ret; + + if (async_tx_test_ack(&desc->txd)) + return -EINTR; + + /* + * On first invocation this shouldn't be necessary, the call to + * ipu_init_channel_buffer() above will set addresses for us, so we + * could make it conditional on status >= IPU_CHANNEL_ENABLED, but + * doing it again shouldn't hurt either. + */ + ret = ipu_update_channel_buffer(ichan, buf_idx, + sg_dma_address(sg)); + + if (ret < 0) { + dev_err(dev, "Updating sg %p on channel 0x%x buffer %d failed!\n", + sg, chan_id, buf_idx); + return ret; + } + + ipu_select_buffer(chan_id, buf_idx); + dev_dbg(dev, "Updated sg %p on channel 0x%x buffer %d\n", + sg, chan_id, buf_idx); + + return 0; +} + +/* Called under spin_lock_irqsave(&ichan->lock) */ static int ipu_submit_channel_buffers(struct idmac_channel *ichan, struct idmac_tx_desc *desc) { @@ -815,20 +854,10 @@ static int ipu_submit_channel_buffers(struct idmac_channel *ichan, if (!ichan->sg[i]) { ichan->sg[i] = sg; - /* - * On first invocation this shouldn't be necessary, the - * call to ipu_init_channel_buffer() above will set - * addresses for us, so we could make it conditional - * on status >= IPU_CHANNEL_ENABLED, but doing it again - * shouldn't hurt either. - */ - ret = ipu_update_channel_buffer(ichan->dma_chan.chan_id, i, - sg_dma_address(sg)); + ret = ipu_submit_buffer(ichan, desc, sg, i); if (ret < 0) return ret; - ipu_select_buffer(ichan->dma_chan.chan_id, i); - sg = sg_next(sg); } } @@ -842,19 +871,22 @@ static dma_cookie_t idmac_tx_submit(struct dma_async_tx_descriptor *tx) struct idmac_channel *ichan = to_idmac_chan(tx->chan); struct idmac *idmac = to_idmac(tx->chan->device); struct ipu *ipu = to_ipu(idmac); + struct device *dev = &ichan->dma_chan.dev->device; dma_cookie_t cookie; unsigned long flags; + int ret; /* Sanity check */ if (!list_empty(&desc->list)) { /* The descriptor doesn't belong to client */ - dev_err(&ichan->dma_chan.dev->device, - "Descriptor %p not prepared!\n", tx); + dev_err(dev, "Descriptor %p not prepared!\n", tx); return -EBUSY; } mutex_lock(&ichan->chan_mutex); + async_tx_clear_ack(tx); + if (ichan->status < IPU_CHANNEL_READY) { struct idmac_video_param *video = &ichan->params.video; /* @@ -878,16 +910,7 @@ static dma_cookie_t idmac_tx_submit(struct dma_async_tx_descriptor *tx) goto out; } - /* ipu->lock can be taken under ichan->lock, but not v.v. */ - spin_lock_irqsave(&ichan->lock, flags); - - /* submit_buffers() atomically verifies and fills empty sg slots */ - cookie = ipu_submit_channel_buffers(ichan, desc); - - spin_unlock_irqrestore(&ichan->lock, flags); - - if (cookie < 0) - goto out; + dev_dbg(dev, "Submitting sg %p\n", &desc->sg[0]); cookie = ichan->dma_chan.cookie; @@ -897,24 +920,40 @@ static dma_cookie_t idmac_tx_submit(struct dma_async_tx_descriptor *tx) /* from dmaengine.h: "last cookie value returned to client" */ ichan->dma_chan.cookie = cookie; tx->cookie = cookie; + + /* ipu->lock can be taken under ichan->lock, but not v.v. */ spin_lock_irqsave(&ichan->lock, flags); + list_add_tail(&desc->list, &ichan->queue); + /* submit_buffers() atomically verifies and fills empty sg slots */ + ret = ipu_submit_channel_buffers(ichan, desc); + spin_unlock_irqrestore(&ichan->lock, flags); + if (ret < 0) { + cookie = ret; + goto dequeue; + } + if (ichan->status < IPU_CHANNEL_ENABLED) { - int ret = ipu_enable_channel(idmac, ichan); + ret = ipu_enable_channel(idmac, ichan); if (ret < 0) { cookie = ret; - spin_lock_irqsave(&ichan->lock, flags); - list_del_init(&desc->list); - spin_unlock_irqrestore(&ichan->lock, flags); - tx->cookie = cookie; - ichan->dma_chan.cookie = cookie; + goto dequeue; } } dump_idmac_reg(ipu); +dequeue: + if (cookie < 0) { + spin_lock_irqsave(&ichan->lock, flags); + list_del_init(&desc->list); + spin_unlock_irqrestore(&ichan->lock, flags); + tx->cookie = cookie; + ichan->dma_chan.cookie = cookie; + } + out: mutex_unlock(&ichan->chan_mutex); @@ -1161,6 +1200,24 @@ static int ipu_disable_channel(struct idmac *idmac, struct idmac_channel *ichan, return 0; } +static struct scatterlist *idmac_sg_next(struct idmac_channel *ichan, + struct idmac_tx_desc **desc, struct scatterlist *sg) +{ + struct scatterlist *sgnew = sg ? sg_next(sg) : NULL; + + if (sgnew) + /* next sg-element in this list */ + return sgnew; + + if ((*desc)->list.next == &ichan->queue) + /* No more descriptors on the queue */ + return NULL; + + /* Fetch next descriptor */ + *desc = list_entry((*desc)->list.next, struct idmac_tx_desc, list); + return (*desc)->sg; +} + /* * We have several possibilities here: * current BUF next BUF @@ -1176,23 +1233,46 @@ static int ipu_disable_channel(struct idmac *idmac, struct idmac_channel *ichan, static irqreturn_t idmac_interrupt(int irq, void *dev_id) { struct idmac_channel *ichan = dev_id; + struct device *dev = &ichan->dma_chan.dev->device; unsigned int chan_id = ichan->dma_chan.chan_id; struct scatterlist **sg, *sgnext, *sgnew = NULL; /* Next transfer descriptor */ - struct idmac_tx_desc *desc = NULL, *descnew; + struct idmac_tx_desc *desc, *descnew; dma_async_tx_callback callback; void *callback_param; bool done = false; - u32 ready0 = idmac_read_ipureg(&ipu_data, IPU_CHA_BUF0_RDY), - ready1 = idmac_read_ipureg(&ipu_data, IPU_CHA_BUF1_RDY), - curbuf = idmac_read_ipureg(&ipu_data, IPU_CHA_CUR_BUF); + u32 ready0, ready1, curbuf, err; + unsigned long flags; /* IDMAC has cleared the respective BUFx_RDY bit, we manage the buffer */ - pr_debug("IDMAC irq %d\n", irq); + dev_dbg(dev, "IDMAC irq %d, buf %d\n", irq, ichan->active_buffer); + + spin_lock_irqsave(&ipu_data.lock, flags); + + ready0 = idmac_read_ipureg(&ipu_data, IPU_CHA_BUF0_RDY); + ready1 = idmac_read_ipureg(&ipu_data, IPU_CHA_BUF1_RDY); + curbuf = idmac_read_ipureg(&ipu_data, IPU_CHA_CUR_BUF); + err = idmac_read_ipureg(&ipu_data, IPU_INT_STAT_4); + + if (err & (1 << chan_id)) { + idmac_write_ipureg(&ipu_data, 1 << chan_id, IPU_INT_STAT_4); + spin_unlock_irqrestore(&ipu_data.lock, flags); + /* + * Doing this + * ichan->sg[0] = ichan->sg[1] = NULL; + * you can force channel re-enable on the next tx_submit(), but + * this is dirty - think about descriptors with multiple + * sg elements. + */ + dev_warn(dev, "NFB4EOF on channel %d, ready %x, %x, cur %x\n", + chan_id, ready0, ready1, curbuf); + return IRQ_HANDLED; + } + spin_unlock_irqrestore(&ipu_data.lock, flags); + /* Other interrupts do not interfere with this channel */ spin_lock(&ichan->lock); - if (unlikely(chan_id != IDMAC_SDC_0 && chan_id != IDMAC_SDC_1 && ((curbuf >> chan_id) & 1) == ichan->active_buffer)) { int i = 100; @@ -1207,19 +1287,23 @@ static irqreturn_t idmac_interrupt(int irq, void *dev_id) if (!i) { spin_unlock(&ichan->lock); - dev_dbg(ichan->dma_chan.device->dev, + dev_dbg(dev, "IRQ on active buffer on channel %x, active " "%d, ready %x, %x, current %x!\n", chan_id, ichan->active_buffer, ready0, ready1, curbuf); return IRQ_NONE; - } + } else + dev_dbg(dev, + "Buffer deactivated on channel %x, active " + "%d, ready %x, %x, current %x, rest %d!\n", chan_id, + ichan->active_buffer, ready0, ready1, curbuf, i); } if (unlikely((ichan->active_buffer && (ready1 >> chan_id) & 1) || (!ichan->active_buffer && (ready0 >> chan_id) & 1) )) { spin_unlock(&ichan->lock); - dev_dbg(ichan->dma_chan.device->dev, + dev_dbg(dev, "IRQ with active buffer still ready on channel %x, " "active %d, ready %x, %x!\n", chan_id, ichan->active_buffer, ready0, ready1); @@ -1227,8 +1311,9 @@ static irqreturn_t idmac_interrupt(int irq, void *dev_id) } if (unlikely(list_empty(&ichan->queue))) { + ichan->sg[ichan->active_buffer] = NULL; spin_unlock(&ichan->lock); - dev_err(ichan->dma_chan.device->dev, + dev_err(dev, "IRQ without queued buffers on channel %x, active %d, " "ready %x, %x!\n", chan_id, ichan->active_buffer, ready0, ready1); @@ -1243,40 +1328,44 @@ static irqreturn_t idmac_interrupt(int irq, void *dev_id) sg = &ichan->sg[ichan->active_buffer]; sgnext = ichan->sg[!ichan->active_buffer]; + if (!*sg) { + spin_unlock(&ichan->lock); + return IRQ_HANDLED; + } + + desc = list_entry(ichan->queue.next, struct idmac_tx_desc, list); + descnew = desc; + + dev_dbg(dev, "IDMAC irq %d, dma 0x%08x, next dma 0x%08x, current %d, curbuf 0x%08x\n", + irq, sg_dma_address(*sg), sgnext ? sg_dma_address(sgnext) : 0, ichan->active_buffer, curbuf); + + /* Find the descriptor of sgnext */ + sgnew = idmac_sg_next(ichan, &descnew, *sg); + if (sgnext != sgnew) + dev_err(dev, "Submitted buffer %p, next buffer %p\n", sgnext, sgnew); + /* * if sgnext == NULL sg must be the last element in a scatterlist and * queue must be empty */ if (unlikely(!sgnext)) { - if (unlikely(sg_next(*sg))) { - dev_err(ichan->dma_chan.device->dev, - "Broken buffer-update locking on channel %x!\n", - chan_id); - /* We'll let the user catch up */ + if (!WARN_ON(sg_next(*sg))) + dev_dbg(dev, "Underrun on channel %x\n", chan_id); + ichan->sg[!ichan->active_buffer] = sgnew; + + if (unlikely(sgnew)) { + ipu_submit_buffer(ichan, descnew, sgnew, !ichan->active_buffer); } else { - /* Underrun */ + spin_lock_irqsave(&ipu_data.lock, flags); ipu_ic_disable_task(&ipu_data, chan_id); - dev_dbg(ichan->dma_chan.device->dev, - "Underrun on channel %x\n", chan_id); + spin_unlock_irqrestore(&ipu_data.lock, flags); ichan->status = IPU_CHANNEL_READY; /* Continue to check for complete descriptor */ } } - desc = list_entry(ichan->queue.next, struct idmac_tx_desc, list); - - /* First calculate and submit the next sg element */ - if (likely(sgnext)) - sgnew = sg_next(sgnext); - - if (unlikely(!sgnew)) { - /* Start a new scatterlist, if any queued */ - if (likely(desc->list.next != &ichan->queue)) { - descnew = list_entry(desc->list.next, - struct idmac_tx_desc, list); - sgnew = &descnew->sg[0]; - } - } + /* Calculate and submit the next sg element */ + sgnew = idmac_sg_next(ichan, &descnew, sgnew); if (unlikely(!sg_next(*sg)) || !sgnext) { /* @@ -1289,17 +1378,13 @@ static irqreturn_t idmac_interrupt(int irq, void *dev_id) *sg = sgnew; - if (likely(sgnew)) { - int ret; - - ret = ipu_update_channel_buffer(chan_id, ichan->active_buffer, - sg_dma_address(*sg)); - if (ret < 0) - dev_err(ichan->dma_chan.device->dev, - "Failed to update buffer on channel %x buffer %d!\n", - chan_id, ichan->active_buffer); - else - ipu_select_buffer(chan_id, ichan->active_buffer); + if (likely(sgnew) && + ipu_submit_buffer(ichan, descnew, sgnew, ichan->active_buffer) < 0) { + callback = desc->txd.callback; + callback_param = desc->txd.callback_param; + spin_unlock(&ichan->lock); + callback(callback_param); + spin_lock(&ichan->lock); } /* Flip the active buffer - even if update above failed */ @@ -1327,13 +1412,20 @@ static void ipu_gc_tasklet(unsigned long arg) struct idmac_channel *ichan = ipu->channel + i; struct idmac_tx_desc *desc; unsigned long flags; - int j; + struct scatterlist *sg; + int j, k; for (j = 0; j < ichan->n_tx_desc; j++) { desc = ichan->desc + j; spin_lock_irqsave(&ichan->lock, flags); if (async_tx_test_ack(&desc->txd)) { list_move(&desc->list, &ichan->free_list); + for_each_sg(desc->sg, sg, desc->sg_len, k) { + if (ichan->sg[0] == sg) + ichan->sg[0] = NULL; + else if (ichan->sg[1] == sg) + ichan->sg[1] = NULL; + } async_tx_clear_ack(&desc->txd); } spin_unlock_irqrestore(&ichan->lock, flags); @@ -1341,13 +1433,7 @@ static void ipu_gc_tasklet(unsigned long arg) } } -/* - * At the time .device_alloc_chan_resources() method is called, we cannot know, - * whether the client will accept the channel. Thus we must only check, if we - * can satisfy client's request but the only real criterion to verify, whether - * the client has accepted our offer is the client_count. That's why we have to - * perform the rest of our allocation tasks on the first call to this function. - */ +/* Just allocate and initialise a transfer descriptor. */ static struct dma_async_tx_descriptor *idmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len, enum dma_data_direction direction, unsigned long tx_flags) @@ -1432,8 +1518,7 @@ static void __idmac_terminate_all(struct dma_chan *chan) struct idmac_tx_desc *desc = ichan->desc + i; if (list_empty(&desc->list)) /* Descriptor was prepared, but not submitted */ - list_add(&desc->list, - &ichan->free_list); + list_add(&desc->list, &ichan->free_list); async_tx_clear_ack(&desc->txd); } @@ -1476,15 +1561,22 @@ static int idmac_alloc_chan_resources(struct dma_chan *chan) goto eimap; ichan->eof_irq = ret; - ret = request_irq(ichan->eof_irq, idmac_interrupt, 0, - ichan->eof_name, ichan); - if (ret < 0) - goto erirq; + + /* + * Important to first disable the channel, because maybe someone + * used it before us, e.g., the bootloader + */ + ipu_disable_channel(idmac, ichan, true); ret = ipu_init_channel(idmac, ichan); if (ret < 0) goto eichan; + ret = request_irq(ichan->eof_irq, idmac_interrupt, 0, + ichan->eof_name, ichan); + if (ret < 0) + goto erirq; + ichan->status = IPU_CHANNEL_INITIALIZED; dev_dbg(&ichan->dma_chan.dev->device, "Found channel 0x%x, irq %d\n", @@ -1492,9 +1584,9 @@ static int idmac_alloc_chan_resources(struct dma_chan *chan) return ret; -eichan: - free_irq(ichan->eof_irq, ichan); erirq: + ipu_uninit_channel(idmac, ichan); +eichan: ipu_irq_unmap(ichan->dma_chan.chan_id); eimap: return ret; @@ -1600,7 +1692,7 @@ static void ipu_idmac_exit(struct ipu *ipu) * IPU common probe / remove */ -static int ipu_probe(struct platform_device *pdev) +static int __init ipu_probe(struct platform_device *pdev) { struct ipu_platform_data *pdata = pdev->dev.platform_data; struct resource *mem_ipu, *mem_ic; -- 1.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/