[PATCH] remove non-cleanroom pwc driver compression

The original pwc author raised some questions about the reverse
engineering of the decompressor algorithms used in the pwc driver.
Having done some detailed investigation it appears those concerns that
clean room policy was not followed are reasonable.  I've also had a
friendly discussion with Philips to ask their view on this.

This removes the problem items of code which reduces the pwc
functionality in the kernel a little but leaves all the framework for
setup that will be needed for decompressors in user space (where they
eventually belong).  This change set is designed to be the minimal risk
change set given that 2.6.12 is hopefully close to hand, with a view to
merging the much updated pwc code in 2.6.13 series kernels.

Someone else can then redo the decompressors properly (clean room) in
user space.

Note that while its easy to say that it should have been caught earlier,
but the violation was really only obvious to someone who had access to
both the proprietary source and the 'GPL' source.

drivers/usb/media/pwc/Makefile

 ifneq ($(KERNELRELEASE),)
 
-pwc-objs	:= pwc-if.o pwc-misc.o pwc-ctrl.o pwc-uncompress.o pwc-dec1.o pwc-dec23.o pwc-kiara.o pwc-timon.o
+pwc-objs	:= pwc-if.o pwc-misc.o pwc-ctrl.o pwc-uncompress.o pwc-timon.o pwc-kiara.o
 
 obj-$(CONFIG_USB_PWC) += pwc.o
 

drivers/usb/media/pwc/pwc-ctrl.c

@@ -246,7 +246,7 @@ static inline int set_video_mode_Nala(struct pwc_device *pdev, int size, int fra
 	   switch(pdev->type) {
 	     case 645:
 	     case 646:
-	       pwc_dec1_init(pdev->type, pdev->release, buf, pdev->decompress_data);
+/*	       pwc_dec1_init(pdev->type, pdev->release, buf, pdev->decompress_data); */
 	       break;
 
 	     case 675:
@@ -256,7 +256,7 @@ static inline int set_video_mode_Nala(struct pwc_device *pdev, int size, int fra
 	     case 730:
 	     case 740:
 	     case 750:
-	       pwc_dec23_init(pdev->type, pdev->release, buf, pdev->decompress_data);
+/*	       pwc_dec23_init(pdev->type, pdev->release, buf, pdev->decompress_data); */
 	       break;
 	   }
 	}
@@ -318,8 +318,8 @@ static inline int set_video_mode_Timon(struct pwc_device *pdev, int size, int fr
 	if (ret < 0)
 		return ret;
 
-	if (pChoose->bandlength > 0 && pdev->vpalette != VIDEO_PALETTE_RAW)
-	   pwc_dec23_init(pdev->type, pdev->release, buf, pdev->decompress_data);
+/* 	if (pChoose->bandlength > 0 && pdev->vpalette != VIDEO_PALETTE_RAW)
+	   pwc_dec23_init(pdev->type, pdev->release, buf, pdev->decompress_data); */
 
 	pdev->cmd_len = 13;
 	memcpy(pdev->cmd_buf, buf, 13);
@@ -397,8 +397,8 @@ static inline int set_video_mode_Kiara(struct pwc_device *pdev, int size, int fr
 	if (ret < 0)
 		return ret;
 
-	if (pChoose->bandlength > 0 && pdev->vpalette != VIDEO_PALETTE_RAW)
-	  pwc_dec23_init(pdev->type, pdev->release, buf, pdev->decompress_data);
+/*	if (pChoose->bandlength > 0 && pdev->vpalette != VIDEO_PALETTE_RAW)
+	  pwc_dec23_init(pdev->type, pdev->release, buf, pdev->decompress_data); */
 
 	pdev->cmd_len = 12;
 	memcpy(pdev->cmd_buf, buf, 12);

drivers/usb/media/pwc/pwc-dec1.c

-/* Linux driver for Philips webcam
-   Decompression for chipset version 1
-   (C) 2004      Luc Saillard (luc@saillard.org)
-
-   NOTE: this version of pwc is an unofficial (modified) release of pwc & pcwx
-   driver and thus may have bugs that are not present in the original version.
-   Please send bug reports and support requests to <luc@saillard.org>.
-   The decompression routines have been implemented by reverse-engineering the
-   Nemosoft binary pwcx module. Caveat emptor.
-
-   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-*/
-
-
-
-#include "pwc-dec1.h"
-
-
-void pwc_dec1_init(int type, int release, void *buffer, void *table)
-{
-
-}
-
-void pwc_dec1_exit(void)
-{
-
-
-
-}
-

drivers/usb/media/pwc/pwc-dec1.h

-/* Linux driver for Philips webcam
-   (C) 2004      Luc Saillard (luc@saillard.org)
-
-   NOTE: this version of pwc is an unofficial (modified) release of pwc & pcwx
-   driver and thus may have bugs that are not present in the original version.
-   Please send bug reports and support requests to <luc@saillard.org>.
-   The decompression routines have been implemented by reverse-engineering the
-   Nemosoft binary pwcx module. Caveat emptor.
-
-   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-*/
-
-
-
-#ifndef PWC_DEC1_H
-#define PWC_DEC1_H
-
-void pwc_dec1_init(int type, int release, void *buffer, void *private_data);
-void pwc_dec1_exit(void);
-
-#endif
-
-
-

drivers/usb/media/pwc/pwc-dec23.h

-/* Linux driver for Philips webcam
-   (C) 2004      Luc Saillard (luc@saillard.org)
-
-   NOTE: this version of pwc is an unofficial (modified) release of pwc & pcwx
-   driver and thus may have bugs that are not present in the original version.
-   Please send bug reports and support requests to <luc@saillard.org>.
-   The decompression routines have been implemented by reverse-engineering the
-   Nemosoft binary pwcx module. Caveat emptor.
-
-   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-*/
-
-#ifndef PWC_DEC23_H
-#define PWC_DEC23_H
-
-struct pwc_dec23_private
-{
-  unsigned char xx,yy,zz,zzmask;
-
-  unsigned char table_0004[2*0x4000];
-  unsigned char table_8004[2*0x1000];
-  unsigned int  table_a004[256*12];
-
-  unsigned char table_d004[8*256];
-  unsigned int  table_d800[256];
-  unsigned int  table_dc00[256];
-};
-
-
-void pwc_dec23_init(int type, int release, unsigned char *buffer, void *private_data);
-void pwc_dec23_exit(void);
-void pwc_dec23_decompress(const struct pwc_coord *image,
-                            const struct pwc_coord *view,
-			    const struct pwc_coord *offset,
-			    const void *src,
-			    void *dst,
-			    int flags,
-			    const void *data,
-			    int bandlength);
-
-
-
-#endif
-
-
-

drivers/usb/media/pwc/pwc-if.c

@@ -68,8 +68,6 @@
 #include "pwc-ioctl.h"
 #include "pwc-kiara.h"
 #include "pwc-timon.h"
-#include "pwc-dec23.h"
-#include "pwc-dec1.h"
 #include "pwc-uncompress.h"
 
 /* Function prototypes and driver templates */
@@ -322,6 +320,7 @@ static int pwc_allocate_buffers(struct pwc_device *pdev)
 	  case 730:
 	  case 740:
 	  case 750:
+#if 0	  
 	    Trace(TRACE_MEMORY,"private_data(%zu)\n",sizeof(struct pwc_dec23_private));
 	    kbuf = kmalloc(sizeof(struct pwc_dec23_private), GFP_KERNEL);	/* Timon & Kiara */
 	    break;
@@ -330,6 +329,8 @@ static int pwc_allocate_buffers(struct pwc_device *pdev)
 	    /* TODO & FIXME */
 	    kbuf = kmalloc(sizeof(struct pwc_dec23_private), GFP_KERNEL);
 	    break;
+#endif	 
+	;
 	 }
 	if (kbuf == NULL) {
 	   Err("Failed to allocate decompress table.\n");
@@ -1131,11 +1132,11 @@ static int pwc_video_close(struct inode *inode, struct file *file)
 	  case 730:
 	  case 740:
 	  case 750:
-	    pwc_dec23_exit();	/* Timon & Kiara */
+/*	    pwc_dec23_exit();	*//* Timon & Kiara */
 	    break;
 	  case 645:
 	  case 646:
-	    pwc_dec1_exit();
+/*	    pwc_dec1_exit(); */
 	    break;
 	 }
 

drivers/usb/media/pwc/pwc-uncompress.c

@@ -122,6 +122,7 @@ int pwc_decompress(struct pwc_device *pdev)
 
 		switch (pdev->type)
 		 {
+#if 0		 
 		  case 675:
 		  case 680:
 		  case 690:
@@ -137,6 +138,7 @@ int pwc_decompress(struct pwc_device *pdev)
 		  case 645:
 		  case 646:
 		    /* TODO & FIXME */
+#endif		    
 		    return -ENXIO; /* No such device or address: missing decompressor */
 		    break;
 		 }