/* em28xx-core.c - driver for Empia EM2800/EM2820/2840 USB video capture devices Copyright (C) 2005 Ludovico Cavedon Markus Rechberger Mauro Carvalho Chehab Sascha Sommer This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #include #include #include #include "em28xx.h" /* #define ENABLE_DEBUG_ISOC_FRAMES */ static unsigned int core_debug = 0; module_param(core_debug,int,0644); MODULE_PARM_DESC(core_debug,"enable debug messages [core]"); #define em28xx_coredbg(fmt, arg...) do {\ if (core_debug) \ printk(KERN_INFO "%s %s :"fmt, \ dev->name, __FUNCTION__ , ##arg); } while (0) static unsigned int reg_debug = 0; module_param(reg_debug,int,0644); MODULE_PARM_DESC(reg_debug,"enable debug messages [URB reg]"); #define em28xx_regdbg(fmt, arg...) do {\ if (reg_debug) \ printk(KERN_INFO "%s %s :"fmt, \ dev->name, __FUNCTION__ , ##arg); } while (0) static unsigned int isoc_debug = 0; module_param(isoc_debug,int,0644); MODULE_PARM_DESC(isoc_debug,"enable debug messages [isoc transfers]"); #define em28xx_isocdbg(fmt, arg...) do {\ if (isoc_debug) \ printk(KERN_INFO "%s %s :"fmt, \ dev->name, __FUNCTION__ , ##arg); } while (0) static int alt = EM28XX_PINOUT; module_param(alt, int, 0644); MODULE_PARM_DESC(alt, "alternate setting to use for video endpoint"); #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15) static void *rvmalloc(size_t size) { void *mem; unsigned long adr; size = PAGE_ALIGN(size); mem = vmalloc_32((unsigned long)size); if (!mem) return NULL; adr = (unsigned long)mem; while (size > 0) { SetPageReserved(vmalloc_to_page((void *)adr)); adr += PAGE_SIZE; size -= PAGE_SIZE; } return mem; } static void rvfree(void *mem, size_t size) { unsigned long adr; if (!mem) return; size = PAGE_ALIGN(size); adr = (unsigned long)mem; while (size > 0) { ClearPageReserved(vmalloc_to_page((void *)adr)); adr += PAGE_SIZE; size -= PAGE_SIZE; } vfree(mem); } #endif /* * em28xx_request_buffers() * allocate a number of buffers */ u32 em28xx_request_buffers(struct em28xx *dev, u32 count) { const size_t imagesize = PAGE_ALIGN(dev->frame_size); /*needs to be page aligned cause the buffers can be mapped individually! */ void *buff = NULL; u32 i; em28xx_coredbg("requested %i buffers with size %zi", count, imagesize); if (count > EM28XX_NUM_FRAMES) count = EM28XX_NUM_FRAMES; dev->num_frames = count; while (dev->num_frames > 0) { #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15) if ((buff = rvmalloc(dev->num_frames * imagesize))) { #else if ((buff = vmalloc_32(dev->num_frames * imagesize))) { #endif memset(buff, 0, dev->num_frames * imagesize); break; } dev->num_frames--; } for (i = 0; i < dev->num_frames; i++) { dev->frame[i].bufmem = buff + i * imagesize; dev->frame[i].buf.index = i; dev->frame[i].buf.m.offset = i * imagesize; dev->frame[i].buf.length = dev->frame_size; dev->frame[i].buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; dev->frame[i].buf.sequence = 0; dev->frame[i].buf.field = V4L2_FIELD_NONE; dev->frame[i].buf.memory = V4L2_MEMORY_MMAP; dev->frame[i].buf.flags = 0; } return dev->num_frames; } /* * em28xx_queue_unusedframes() * add all frames that are not currently in use to the inbuffer queue */ void em28xx_queue_unusedframes(struct em28xx *dev) { unsigned long lock_flags; u32 i; for (i = 0; i < dev->num_frames; i++) if (dev->frame[i].state == F_UNUSED) { dev->frame[i].state = F_QUEUED; spin_lock_irqsave(&dev->queue_lock, lock_flags); list_add_tail(&dev->frame[i].frame, &dev->inqueue); spin_unlock_irqrestore(&dev->queue_lock, lock_flags); } } /* * em28xx_release_buffers() * free frame buffers */ void em28xx_release_buffers(struct em28xx *dev) { if (dev->num_frames) { #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15) rvfree(dev->frame[0].bufmem, dev->num_frames * PAGE_ALIGN(dev->frame[0].buf.length)); #else vfree(dev->frame[0].bufmem); #endif dev->num_frames = 0; } } /* * em28xx_read_reg_req() * reads data from the usb device specifying bRequest */ int em28xx_read_reg_req_len(struct em28xx *dev, u8 req, u16 reg, char *buf, int len) { int ret, byte; if (dev->state & DEV_DISCONNECTED) return(-ENODEV); em28xx_regdbg("req=%02x, reg=%02x ", req, reg); ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), req, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE, 0x0000, reg, buf, len, HZ); if (reg_debug){ printk(ret < 0 ? " failed!\n" : "%02x values: ", ret); for (byte = 0; byte < len; byte++) { printk(" %02x", buf[byte]); } printk("\n"); } return ret; } /* * em28xx_read_reg_req() * reads data from the usb device specifying bRequest */ int em28xx_read_reg_req(struct em28xx *dev, u8 req, u16 reg) { u8 val; int ret; if (dev->state & DEV_DISCONNECTED) return(-ENODEV); em28xx_regdbg("req=%02x, reg=%02x:", req, reg); ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), req, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE, 0x0000, reg, &val, 1, HZ); if (reg_debug) printk(ret < 0 ? " failed!\n" : "%02x\n", val); if (ret < 0) return ret; return val; } int em28xx_read_reg(struct em28xx *dev, u16 reg) { return em28xx_read_reg_req(dev, USB_REQ_GET_STATUS, reg); } /* * em28xx_write_regs_req() * sends data to the usb device, specifying bRequest */ int em28xx_write_regs_req(struct em28xx *dev, u8 req, u16 reg, char *buf, int len) { int ret; /*usb_control_msg seems to expect a kmalloced buffer */ unsigned char *bufs; if (dev->state & DEV_DISCONNECTED) return(-ENODEV); bufs = kmalloc(len, GFP_KERNEL); em28xx_regdbg("req=%02x reg=%02x:", req, reg); if (reg_debug) { int i; for (i = 0; i < len; ++i) printk (" %02x", (unsigned char)buf[i]); printk ("\n"); } if (!bufs) return -ENOMEM; memcpy(bufs, buf, len); ret = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0), req, USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE, 0x0000, reg, bufs, len, HZ); msleep(5); /* FIXME: magic number */ kfree(bufs); return ret; } int em28xx_write_regs(struct em28xx *dev, u16 reg, char *buf, int len) { return em28xx_write_regs_req(dev, USB_REQ_GET_STATUS, reg, buf, len); } /* * em28xx_write_reg_bits() * sets only some bits (specified by bitmask) of a register, by first reading * the actual value */ int em28xx_write_reg_bits(struct em28xx *dev, u16 reg, u8 val, u8 bitmask) { int oldval; u8 newval; if ((oldval = em28xx_read_reg(dev, reg)) < 0) return oldval; newval = (((u8) oldval) & ~bitmask) | (val & bitmask); return em28xx_write_regs(dev, reg, &newval, 1); } /* * em28xx_write_ac97() * write a 16 bit value to the specified AC97 address (LSB first!) */ int em28xx_write_ac97(struct em28xx *dev, u8 reg, u8 * val) { int ret; u8 addr = reg & 0x7f; if ((ret = em28xx_write_regs(dev, AC97LSB_REG, val, 2)) < 0) return ret; if ((ret = em28xx_write_regs(dev, AC97ADDR_REG, &addr, 1)) < 0) return ret; if ((ret = em28xx_read_reg(dev, AC97BUSY_REG)) < 0) return ret; else if (((u8) ret) & 0x01) { em28xx_warn ("AC97 command still being executed: not handled properly!\n"); } return 0; } int em28xx_audio_analog_set(struct em28xx *dev) { char s[2] = { 0x00, 0x00 }; s[0] |= 0x1f - dev->volume; s[1] |= 0x1f - dev->volume; if (dev->mute) s[1] |= 0x80; return em28xx_write_ac97(dev, MASTER_AC97, s); } #if 0 int em28xx_audio_analog_mute(struct em28xx *dev, int mute) { /* (un)mute master mixer with maximum volume level */ return em28xx_write_ac97(dev, MASTER_AC97, mute ? "\x00\x80" : "\x00\x00"); } #endif int em28xx_colorlevels_set_default(struct em28xx *dev) { em28xx_write_regs(dev, YGAIN_REG, "\x10", 1); /* contrast */ em28xx_write_regs(dev, YOFFSET_REG, "\x00", 1); /* brightness */ em28xx_write_regs(dev, UVGAIN_REG, "\x10", 1); /* saturation */ em28xx_write_regs(dev, UOFFSET_REG, "\x00", 1); em28xx_write_regs(dev, VOFFSET_REG, "\x00", 1); em28xx_write_regs(dev, SHARPNESS_REG, "\x00", 1); em28xx_write_regs(dev, GAMMA_REG, "\x20", 1); em28xx_write_regs(dev, RGAIN_REG, "\x20", 1); em28xx_write_regs(dev, GGAIN_REG, "\x20", 1); em28xx_write_regs(dev, BGAIN_REG, "\x20", 1); em28xx_write_regs(dev, ROFFSET_REG, "\x00", 1); em28xx_write_regs(dev, GOFFSET_REG, "\x00", 1); return em28xx_write_regs(dev, BOFFSET_REG, "\x00", 1); } int em28xx_capture_start(struct em28xx *dev, int start) { int ret; /* FIXME: which is the best order? */ /* video registers are sampled by VREF */ if ((ret = em28xx_write_reg_bits(dev, USBSUSP_REG, start ? 0x10 : 0x00, 0x10)) < 0) return ret; /* enable video capture */ return em28xx_write_regs(dev, VINENABLE_REG, start ? "\x67" : "\x27", 1); } int em28xx_outfmt_set_yuv422(struct em28xx *dev) { em28xx_write_regs(dev, OUTFMT_REG, "\x34", 1); em28xx_write_regs(dev, VINMODE_REG, "\x10", 1); return em28xx_write_regs(dev, VINCTRL_REG, "\x11", 1); } int em28xx_accumulator_set(struct em28xx *dev, u8 xmin, u8 xmax, u8 ymin, u8 ymax) { em28xx_coredbg("em28xx Scale: (%d,%d)-(%d,%d)\n", xmin, ymin, xmax, ymax); em28xx_write_regs(dev, XMIN_REG, &xmin, 1); em28xx_write_regs(dev, XMAX_REG, &xmax, 1); em28xx_write_regs(dev, YMIN_REG, &ymin, 1); return em28xx_write_regs(dev, YMAX_REG, &ymax, 1); } int em28xx_capture_area_set(struct em28xx *dev, u8 hstart, u8 vstart, u16 width, u16 height) { u8 cwidth = width; u8 cheight = height; u8 overflow = (height >> 7 & 0x02) | (width >> 8 & 0x01); em28xx_coredbg("em28xx Area Set: (%d,%d)\n", (width | (overflow & 2) << 7), (height | (overflow & 1) << 8)); em28xx_write_regs(dev, HSTART_REG, &hstart, 1); em28xx_write_regs(dev, VSTART_REG, &vstart, 1); em28xx_write_regs(dev, CWIDTH_REG, &cwidth, 1); em28xx_write_regs(dev, CHEIGHT_REG, &cheight, 1); return em28xx_write_regs(dev, OFLOW_REG, &overflow, 1); } int em28xx_scaler_set(struct em28xx *dev, u16 h, u16 v) { u8 mode; /* the em2800 scaler only supports scaling down to 50% */ if(dev->is_em2800) mode = (v ? 0x20 : 0x00) | (h ? 0x10 : 0x00); else { u8 buf[2]; buf[0] = h; buf[1] = h >> 8; em28xx_write_regs(dev, HSCALELOW_REG, (char *)buf, 2); buf[0] = v; buf[1] = v >> 8; em28xx_write_regs(dev, VSCALELOW_REG, (char *)buf, 2); /* it seems that both H and V scalers must be active to work correctly */ mode = (h || v)? 0x30: 0x00; } return em28xx_write_reg_bits(dev, COMPR_REG, mode, 0x30); } /* FIXME: this only function read values from dev */ int em28xx_resolution_set(struct em28xx *dev) { int width, height; width = norm_maxw(dev); height = norm_maxh(dev) >> 1; em28xx_outfmt_set_yuv422(dev); em28xx_accumulator_set(dev, 1, (width - 4) >> 2, 1, (height - 4) >> 2); em28xx_capture_area_set(dev, 0, 0, width >> 2, height >> 2); return em28xx_scaler_set(dev, dev->hscale, dev->vscale); } /******************* isoc transfer handling ****************************/ #ifdef ENABLE_DEBUG_ISOC_FRAMES static void em28xx_isoc_dump(struct urb *urb, struct pt_regs *regs) { int len = 0; int ntrans = 0; int i; printk(KERN_DEBUG "isocIrq: sf=%d np=%d ec=%x\n", urb->start_frame, urb->number_of_packets, urb->error_count); for (i = 0; i < urb->number_of_packets; i++) { unsigned char *buf = urb->transfer_buffer + urb->iso_frame_desc[i].offset; int alen = urb->iso_frame_desc[i].actual_length; if (alen > 0) { if (buf[0] == 0x88) { ntrans++; len += alen; } else if (buf[0] == 0x22) { printk(KERN_DEBUG "= l=%d nt=%d bpp=%d\n", len - 4 * ntrans, ntrans, ntrans == 0 ? 0 : len / ntrans); ntrans = 1; len = alen; } else printk(KERN_DEBUG "!\n"); } printk(KERN_DEBUG " n=%d s=%d al=%d %x\n", i, urb->iso_frame_desc[i].status, urb->iso_frame_desc[i].actual_length, (unsigned int) *((unsigned char *)(urb->transfer_buffer + urb->iso_frame_desc[i]. offset))); } } #endif static inline int em28xx_isoc_video(struct em28xx *dev,struct em28xx_frame_t **f, unsigned long *lock_flags, unsigned char buf) { if (!(buf & 0x01)) { if ((*f)->state == F_GRABBING) { /*previous frame is incomplete */ if ((*f)->fieldbytesused < dev->field_size) { (*f)->state = F_ERROR; em28xx_isocdbg ("dropping incomplete bottom field (%i missing bytes)", dev->field_size-(*f)->fieldbytesused); } else { (*f)->state = F_DONE; (*f)->buf.bytesused = dev->frame_size; } } if ((*f)->state == F_DONE || (*f)->state == F_ERROR) { /* move current frame to outqueue and get next free buffer from inqueue */ spin_lock_irqsave(&dev-> queue_lock, *lock_flags); list_move_tail(&(*f)->frame, &dev->outqueue); if (!list_empty(&dev->inqueue)) (*f) = list_entry(dev-> inqueue.next, struct em28xx_frame_t,frame); else (*f) = NULL; spin_unlock_irqrestore(&dev->queue_lock,*lock_flags); } if (!(*f)) { em28xx_isocdbg ("new frame but no buffer is free"); return -1; } do_gettimeofday(&(*f)->buf.timestamp); (*f)->buf.sequence = ++dev->frame_count; (*f)->buf.field = V4L2_FIELD_INTERLACED; (*f)->state = F_GRABBING; (*f)->buf.bytesused = 0; (*f)->top_field = 1; (*f)->fieldbytesused = 0; } else { /* acquiring bottom field */ if ((*f)->state == F_GRABBING) { if (!(*f)->top_field) { (*f)->state = F_ERROR; em28xx_isocdbg ("unexpected begin of bottom field; discarding it"); } else if ((*f)-> fieldbytesused < dev->field_size - 172) { (*f)->state = F_ERROR; em28xx_isocdbg ("dropping incomplete top field (%i missing bytes)", dev->field_size-(*f)->fieldbytesused); } else { (*f)->top_field = 0; (*f)->fieldbytesused = 0; } } } return (0); } static inline void em28xx_isoc_video_copy(struct em28xx *dev, struct em28xx_frame_t **f, unsigned char *buf, int len) { void *fieldstart, *startwrite, *startread; int linesdone, currlinedone, offset, lencopy,remain; if(dev->frame_size != (*f)->buf.length){ em28xx_err("frame_size %i and buf.length %i are different!!!\n",dev->frame_size,(*f)->buf.length); return; } if ((*f)->fieldbytesused + len > dev->field_size) len =dev->field_size - (*f)->fieldbytesused; if (buf[0] != 0x88 && buf[0] != 0x22) { em28xx_isocdbg("frame is not complete\n"); startread = buf; len+=4; } else startread = buf + 4; remain = len; if ((*f)->top_field) fieldstart = (*f)->bufmem; else fieldstart = (*f)->bufmem + dev->bytesperline; linesdone = (*f)->fieldbytesused / dev->bytesperline; currlinedone = (*f)->fieldbytesused % dev->bytesperline; offset = linesdone * dev->bytesperline * 2 + currlinedone; startwrite = fieldstart + offset; lencopy = dev->bytesperline - currlinedone; lencopy = lencopy > remain ? remain : lencopy; memcpy(startwrite, startread, lencopy); remain -= lencopy; while (remain > 0) { startwrite += lencopy + dev->bytesperline; startread += lencopy; if (dev->bytesperline > remain) lencopy = remain; else lencopy = dev->bytesperline; memcpy(startwrite, startread, lencopy); remain -= lencopy; } (*f)->fieldbytesused += len; } /* * em28xx_isoIrq() * handles the incoming isoc urbs and fills the frames from our inqueue */ void em28xx_isocIrq(struct urb *urb, struct pt_regs *regs) { struct em28xx *dev = urb->context; int i, status; struct em28xx_frame_t **f; unsigned long lock_flags; if (!dev) return; #ifdef ENABLE_DEBUG_ISOC_FRAMES if (isoc_debug>1) em28xx_isoc_dump(urb, regs); #endif if (urb->status == -ENOENT) return; f = &dev->frame_current; if (dev->stream == STREAM_INTERRUPT) { dev->stream = STREAM_OFF; if ((*f)) (*f)->state = F_QUEUED; em28xx_isocdbg("stream interrupted"); wake_up_interruptible(&dev->wait_stream); } if ((dev->state & DEV_DISCONNECTED) || (dev->state & DEV_MISCONFIGURED)) return; if (dev->stream == STREAM_ON && !list_empty(&dev->inqueue)) { if (!(*f)) (*f) = list_entry(dev->inqueue.next, struct em28xx_frame_t, frame); for (i = 0; i < urb->number_of_packets; i++) { unsigned char *buf = urb->transfer_buffer + urb->iso_frame_desc[i].offset; int len = urb->iso_frame_desc[i].actual_length - 4; if (urb->iso_frame_desc[i].status) { em28xx_isocdbg("data error: [%d] len=%d, status=%d", i, urb->iso_frame_desc[i].actual_length, urb->iso_frame_desc[i].status); if (urb->iso_frame_desc[i].status != -EPROTO) continue; } if (urb->iso_frame_desc[i].actual_length <= 0) { em28xx_isocdbg("packet %d is empty",i); continue; } if (urb->iso_frame_desc[i].actual_length > dev->max_pkt_size) { em28xx_isocdbg("packet bigger than packet size"); continue; } /*new frame */ if (buf[0] == 0x22 && buf[1] == 0x5a) { em28xx_isocdbg("Video frame, length=%i!",len); if (em28xx_isoc_video(dev,f,&lock_flags,buf[2])) break; } else if (buf[0]==0x33 && buf[1]==0x95 && buf[2]==0x00) { em28xx_isocdbg("VBI HEADER!!!"); } /* actual copying */ if ((*f)->state == F_GRABBING) { em28xx_isoc_video_copy(dev,f,buf, len); } } } for (i = 0; i < urb->number_of_packets; i++) { urb->iso_frame_desc[i].status = 0; urb->iso_frame_desc[i].actual_length = 0; } urb->status = 0; if ((status = usb_submit_urb(urb, GFP_ATOMIC))) { em28xx_errdev("resubmit of urb failed (error=%i)\n", status); dev->state |= DEV_MISCONFIGURED; } wake_up_interruptible(&dev->wait_frame); return; } /* * em28xx_uninit_isoc() * deallocates the buffers and urbs allocated during em28xx_init_iosc() */ void em28xx_uninit_isoc(struct em28xx *dev) { int i; for (i = 0; i < EM28XX_NUM_BUFS; i++) { if (dev->urb[i]) { usb_kill_urb(dev->urb[i]); if (dev->transfer_buffer[i]){ usb_buffer_free(dev->udev,(EM28XX_NUM_PACKETS*dev->max_pkt_size),dev->transfer_buffer[i],dev->urb[i]->transfer_dma); } usb_free_urb(dev->urb[i]); } dev->urb[i] = NULL; dev->transfer_buffer[i] = NULL; } em28xx_capture_start(dev, 0); } /* * em28xx_init_isoc() * allocates transfer buffers and submits the urbs for isoc transfer */ int em28xx_init_isoc(struct em28xx *dev) { /* change interface to 3 which allowes the biggest packet sizes */ int i, errCode; const int sb_size = EM28XX_NUM_PACKETS * dev->max_pkt_size; /* reset streaming vars */ dev->frame_current = NULL; dev->frame_count = 0; /* allocate urbs */ for (i = 0; i < EM28XX_NUM_BUFS; i++) { struct urb *urb; int j, k; /* allocate transfer buffer */ urb = usb_alloc_urb(EM28XX_NUM_PACKETS, GFP_KERNEL); if (!urb){ em28xx_errdev("cannot alloc urb %i\n", i); em28xx_uninit_isoc(dev); return -ENOMEM; } dev->transfer_buffer[i] = usb_buffer_alloc(dev->udev, sb_size, GFP_KERNEL,&urb->transfer_dma); if (!dev->transfer_buffer[i]) { em28xx_errdev ("unable to allocate %i bytes for transfer buffer %i\n", sb_size, i); em28xx_uninit_isoc(dev); return -ENOMEM; } memset(dev->transfer_buffer[i], 0, sb_size); urb->dev = dev->udev; urb->context = dev; urb->pipe = usb_rcvisocpipe(dev->udev, 0x82); urb->transfer_flags = URB_ISO_ASAP; urb->interval = 1; urb->transfer_buffer = dev->transfer_buffer[i]; urb->complete = em28xx_isocIrq; urb->number_of_packets = EM28XX_NUM_PACKETS; urb->transfer_buffer_length = sb_size; for (j = k = 0; j < EM28XX_NUM_PACKETS; j++, k += dev->max_pkt_size) { urb->iso_frame_desc[j].offset = k; urb->iso_frame_desc[j].length = dev->max_pkt_size; } dev->urb[i] = urb; } /* submit urbs */ for (i = 0; i < EM28XX_NUM_BUFS; i++) { errCode = usb_submit_urb(dev->urb[i], GFP_KERNEL); if (errCode) { em28xx_errdev("submit of urb %i failed (error=%i)\n", i, errCode); em28xx_uninit_isoc(dev); return errCode; } } return 0; } int em28xx_set_alternate(struct em28xx *dev) { int errCode, prev_alt = dev->alt; dev->alt = alt; if (dev->alt == 0) { int i; #if 1 /* Always try to get the maximum size value */ for(i=0;i< dev->num_alt; i++) if(dev->alt_max_pkt_size[i]>dev->alt_max_pkt_size[dev->alt]) dev->alt=i; #endif #if 0 /* Should be dependent of horizontal size */ if(dev->is_em2800){ /* always use the max packet size for em2800 based devices */ for(i=0;i< dev->num_alt; i++) if(dev->alt_max_pkt_size[i]>dev->alt_max_pkt_size[dev->alt]) dev->alt=i; }else{ unsigned int min_pkt_size = dev->field_size / 137; /* FIXME: empiric magic number */ em28xx_coredbg("minimum isoc packet size: %u", min_pkt_size); dev->alt = 7; for (i = 0; i < dev->num_alt; i ++) if (dev->alt_max_pkt_size[i] >= min_pkt_size) { dev->alt = i; break; } } #endif } if (dev->alt != prev_alt) { dev->max_pkt_size = dev->alt_max_pkt_size[dev->alt]; em28xx_coredbg("setting alternate %d with wMaxPacketSize=%u\n", dev->alt, dev->max_pkt_size); errCode = usb_set_interface(dev->udev, 0, dev->alt); if (errCode < 0) { em28xx_errdev ("cannot change alternate number to %d (error=%i)\n", dev->alt, errCode); return errCode; } } return 0; }