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* [PATCH] fbdev: Remove udlfb driver
@ 2020-11-30 12:52 Thomas Zimmermann
  2020-11-30 14:31 ` Mikulas Patocka
  0 siblings, 1 reply; 15+ messages in thread
From: Thomas Zimmermann @ 2020-11-30 12:52 UTC (permalink / raw)
  To: daniel.vetter, mpatocka, sam, geert+renesas, bernie, corbet
  Cc: dri-devel, linux-fbdev, linux-doc, Thomas Zimmermann

Udlfb has been superseded by DRM's udl. The DRM driver is better by
any means and actively maintained. Remove udlfb.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 CREDITS                      |    5 +
 Documentation/fb/index.rst   |    1 -
 Documentation/fb/udlfb.rst   |  162 ---
 MAINTAINERS                  |    9 -
 drivers/video/fbdev/Kconfig  |   17 +-
 drivers/video/fbdev/Makefile |    1 -
 drivers/video/fbdev/udlfb.c  | 1994 ----------------------------------
 7 files changed, 6 insertions(+), 2183 deletions(-)
 delete mode 100644 Documentation/fb/udlfb.rst
 delete mode 100644 drivers/video/fbdev/udlfb.c

diff --git a/CREDITS b/CREDITS
index 748301954ab7..fed3518c4dd8 100644
--- a/CREDITS
+++ b/CREDITS
@@ -3620,6 +3620,11 @@ S: 145 Howard St.
 S: Northborough, MA 01532
 S: USA
 
+N: Bernie Thompson
+E: bernie@plugable.com
+W: http://plugable.com/category/projects/udlfb/
+D: DisplayLink USB 2.0 framebuffer driver
+
 N: Doug Thompson
 E: dougthompson@xmission.com
 D: EDAC
diff --git a/Documentation/fb/index.rst b/Documentation/fb/index.rst
index baf02393d8ee..8136c84328e2 100644
--- a/Documentation/fb/index.rst
+++ b/Documentation/fb/index.rst
@@ -36,7 +36,6 @@ Frame Buffer
     sstfb
     tgafb
     tridentfb
-    udlfb
     uvesafb
     vesafb
     viafb
diff --git a/Documentation/fb/udlfb.rst b/Documentation/fb/udlfb.rst
deleted file mode 100644
index 732b37db3504..000000000000
--- a/Documentation/fb/udlfb.rst
+++ /dev/null
@@ -1,162 +0,0 @@
-==============
-What is udlfb?
-==============
-
-This is a driver for DisplayLink USB 2.0 era graphics chips.
-
-DisplayLink chips provide simple hline/blit operations with some compression,
-pairing that with a hardware framebuffer (16MB) on the other end of the
-USB wire.  That hardware framebuffer is able to drive the VGA, DVI, or HDMI
-monitor with no CPU involvement until a pixel has to change.
-
-The CPU or other local resource does all the rendering; optionally compares the
-result with a local shadow of the remote hardware framebuffer to identify
-the minimal set of pixels that have changed; and compresses and sends those
-pixels line-by-line via USB bulk transfers.
-
-Because of the efficiency of bulk transfers and a protocol on top that
-does not require any acks - the effect is very low latency that
-can support surprisingly high resolutions with good performance for
-non-gaming and non-video applications.
-
-Mode setting, EDID read, etc are other bulk or control transfers. Mode
-setting is very flexible - able to set nearly arbitrary modes from any timing.
-
-Advantages of USB graphics in general:
-
- * Ability to add a nearly arbitrary number of displays to any USB 2.0
-   capable system. On Linux, number of displays is limited by fbdev interface
-   (FB_MAX is currently 32). Of course, all USB devices on the same
-   host controller share the same 480Mbs USB 2.0 interface.
-
-Advantages of supporting DisplayLink chips with kernel framebuffer interface:
-
- * The actual hardware functionality of DisplayLink chips matches nearly
-   one-to-one with the fbdev interface, making the driver quite small and
-   tight relative to the functionality it provides.
- * X servers and other applications can use the standard fbdev interface
-   from user mode to talk to the device, without needing to know anything
-   about USB or DisplayLink's protocol at all. A "displaylink" X driver
-   and a slightly modified "fbdev" X driver are among those that already do.
-
-Disadvantages:
-
- * Fbdev's mmap interface assumes a real hardware framebuffer is mapped.
-   In the case of USB graphics, it is just an allocated (virtual) buffer.
-   Writes need to be detected and encoded into USB bulk transfers by the CPU.
-   Accurate damage/changed area notifications work around this problem.
-   In the future, hopefully fbdev will be enhanced with an small standard
-   interface to allow mmap clients to report damage, for the benefit
-   of virtual or remote framebuffers.
- * Fbdev does not arbitrate client ownership of the framebuffer well.
- * Fbcon assumes the first framebuffer it finds should be consumed for console.
- * It's not clear what the future of fbdev is, given the rise of KMS/DRM.
-
-How to use it?
-==============
-
-Udlfb, when loaded as a module, will match against all USB 2.0 generation
-DisplayLink chips (Alex and Ollie family). It will then attempt to read the EDID
-of the monitor, and set the best common mode between the DisplayLink device
-and the monitor's capabilities.
-
-If the DisplayLink device is successful, it will paint a "green screen" which
-means that from a hardware and fbdev software perspective, everything is good.
-
-At that point, a /dev/fb? interface will be present for user-mode applications
-to open and begin writing to the framebuffer of the DisplayLink device using
-standard fbdev calls.  Note that if mmap() is used, by default the user mode
-application must send down damage notifications to trigger repaints of the
-changed regions.  Alternatively, udlfb can be recompiled with experimental
-defio support enabled, to support a page-fault based detection mechanism
-that can work without explicit notification.
-
-The most common client of udlfb is xf86-video-displaylink or a modified
-xf86-video-fbdev X server. These servers have no real DisplayLink specific
-code. They write to the standard framebuffer interface and rely on udlfb
-to do its thing.  The one extra feature they have is the ability to report
-rectangles from the X DAMAGE protocol extension down to udlfb via udlfb's
-damage interface (which will hopefully be standardized for all virtual
-framebuffers that need damage info). These damage notifications allow
-udlfb to efficiently process the changed pixels.
-
-Module Options
-==============
-
-Special configuration for udlfb is usually unnecessary. There are a few
-options, however.
-
-From the command line, pass options to modprobe
-modprobe udlfb fb_defio=0 console=1 shadow=1
-
-Or modify options on the fly at /sys/module/udlfb/parameters directory via
-sudo nano fb_defio
-change the parameter in place, and save the file.
-
-Unplug/replug USB device to apply with new settings
-
-Or for permanent option, create file like /etc/modprobe.d/udlfb.conf with text
-options udlfb fb_defio=0 console=1 shadow=1
-
-Accepted boolean options:
-
-=============== ================================================================
-fb_defio	Make use of the fb_defio (CONFIG_FB_DEFERRED_IO) kernel
-		module to track changed areas of the framebuffer by page faults.
-		Standard fbdev applications that use mmap but that do not
-		report damage, should be able to work with this enabled.
-		Disable when running with X server that supports reporting
-		changed regions via ioctl, as this method is simpler,
-		more stable, and higher performance.
-		default: fb_defio=1
-
-console		Allow fbcon to attach to udlfb provided framebuffers.
-		Can be disabled if fbcon and other clients
-		(e.g. X with --shared-vt) are in conflict.
-		default: console=1
-
-shadow		Allocate a 2nd framebuffer to shadow what's currently across
-		the USB bus in device memory. If any pixels are unchanged,
-		do not transmit. Spends host memory to save USB transfers.
-		Enabled by default. Only disable on very low memory systems.
-		default: shadow=1
-=============== ================================================================
-
-Sysfs Attributes
-================
-
-Udlfb creates several files in /sys/class/graphics/fb?
-Where ? is the sequential framebuffer id of the particular DisplayLink device
-
-======================== ========================================================
-edid			 If a valid EDID blob is written to this file (typically
-			 by a udev rule), then udlfb will use this EDID as a
-			 backup in case reading the actual EDID of the monitor
-			 attached to the DisplayLink device fails. This is
-			 especially useful for fixed panels, etc. that cannot
-			 communicate their capabilities via EDID. Reading
-			 this file returns the current EDID of the attached
-			 monitor (or last backup value written). This is
-			 useful to get the EDID of the attached monitor,
-			 which can be passed to utilities like parse-edid.
-
-metrics_bytes_rendered	 32-bit count of pixel bytes rendered
-
-metrics_bytes_identical  32-bit count of how many of those bytes were found to be
-			 unchanged, based on a shadow framebuffer check
-
-metrics_bytes_sent	 32-bit count of how many bytes were transferred over
-			 USB to communicate the resulting changed pixels to the
-			 hardware. Includes compression and protocol overhead
-
-metrics_cpu_kcycles_used 32-bit count of CPU cycles used in processing the
-			 above pixels (in thousands of cycles).
-
-metrics_reset		 Write-only. Any write to this file resets all metrics
-			 above to zero.  Note that the 32-bit counters above
-			 roll over very quickly. To get reliable results, design
-			 performance tests to start and finish in a very short
-			 period of time (one minute or less is safe).
-======================== ========================================================
-
-Bernie Thompson <bernie@plugable.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index c5a399541d6a..2b445f87e1ef 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5178,15 +5178,6 @@ F:	fs/quota/
 F:	include/linux/quota*.h
 F:	include/uapi/linux/quota*.h
 
-DISPLAYLINK USB 2.0 FRAMEBUFFER DRIVER (UDLFB)
-M:	Bernie Thompson <bernie@plugable.com>
-L:	linux-fbdev@vger.kernel.org
-S:	Maintained
-W:	http://plugable.com/category/projects/udlfb/
-F:	Documentation/fb/udlfb.rst
-F:	drivers/video/fbdev/udlfb.c
-F:	include/video/udlfb.h
-
 DISTRIBUTED LOCK MANAGER (DLM)
 M:	Christine Caulfield <ccaulfie@redhat.com>
 M:	David Teigland <teigland@redhat.com>
diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
index 4f02db65dede..41189b31c5d6 100644
--- a/drivers/video/fbdev/Kconfig
+++ b/drivers/video/fbdev/Kconfig
@@ -558,7 +558,7 @@ config FB_STI
 	  BIOS routines contained in a ROM chip in HP PA-RISC based machines.
 	  Enabling this option will implement the linux framebuffer device
 	  using calls to the STI BIOS routines for initialisation.
-	
+
 	  If you enable this option, you will get a planar framebuffer device
 	  /dev/fb which will work on the most common HP graphic cards of the
 	  NGLE family, including the artist chips (in the 7xx and Bxxx series),
@@ -1939,21 +1939,6 @@ config FB_SMSCUFX
 	  (USB 3.0) devices.
 	  To compile as a module, choose M here: the module name is smscufx.
 
-config FB_UDL
-	tristate "Displaylink USB Framebuffer support"
-	depends on FB && USB
-	select FB_MODE_HELPERS
-	select FB_SYS_FILLRECT
-	select FB_SYS_COPYAREA
-	select FB_SYS_IMAGEBLIT
-	select FB_SYS_FOPS
-	select FB_DEFERRED_IO
-	help
-	  This is a kernel framebuffer driver for DisplayLink USB devices.
-	  Supports fbdev clients like xf86-video-fbdev, kdrive, fbi, and
-	  mplayer -vo fbdev. Supports all USB 2.0 era DisplayLink devices.
-	  To compile as a module, choose M here: the module name is udlfb.
-
 config FB_IBM_GXT4500
 	tristate "Framebuffer support for IBM GXT4000P/4500P/6000P/6500P adaptors"
 	depends on FB
diff --git a/drivers/video/fbdev/Makefile b/drivers/video/fbdev/Makefile
index 477b9624b703..49b5dd0bef02 100644
--- a/drivers/video/fbdev/Makefile
+++ b/drivers/video/fbdev/Makefile
@@ -106,7 +106,6 @@ obj-$(CONFIG_FB_COBALT)           += cobalt_lcdfb.o
 obj-$(CONFIG_FB_IBM_GXT4500)	  += gxt4500.o
 obj-$(CONFIG_FB_PS3)		  += ps3fb.o
 obj-$(CONFIG_FB_SM501)            += sm501fb.o
-obj-$(CONFIG_FB_UDL)		  += udlfb.o
 obj-$(CONFIG_FB_SMSCUFX)	  += smscufx.o
 obj-$(CONFIG_FB_XILINX)           += xilinxfb.o
 obj-$(CONFIG_FB_SH_MOBILE_LCDC)	  += sh_mobile_lcdcfb.o
diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c
deleted file mode 100644
index f9b3c1cb9530..000000000000
--- a/drivers/video/fbdev/udlfb.c
+++ /dev/null
@@ -1,1994 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * udlfb.c -- Framebuffer driver for DisplayLink USB controller
- *
- * Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
- * Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
- * Copyright (C) 2009 Bernie Thompson <bernie@plugable.com>
- *
- * Layout is based on skeletonfb by James Simmons and Geert Uytterhoeven,
- * usb-skeleton by GregKH.
- *
- * Device-specific portions based on information from Displaylink, with work
- * from Florian Echtler, Henrik Bjerregaard Pedersen, and others.
- */
-
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/init.h>
-#include <linux/usb.h>
-#include <linux/uaccess.h>
-#include <linux/mm.h>
-#include <linux/fb.h>
-#include <linux/vmalloc.h>
-#include <linux/slab.h>
-#include <linux/delay.h>
-#include <asm/unaligned.h>
-#include <video/udlfb.h>
-#include "edid.h"
-
-static const struct fb_fix_screeninfo dlfb_fix = {
-	.id =           "udlfb",
-	.type =         FB_TYPE_PACKED_PIXELS,
-	.visual =       FB_VISUAL_TRUECOLOR,
-	.xpanstep =     0,
-	.ypanstep =     0,
-	.ywrapstep =    0,
-	.accel =        FB_ACCEL_NONE,
-};
-
-static const u32 udlfb_info_flags = FBINFO_DEFAULT | FBINFO_READS_FAST |
-		FBINFO_VIRTFB |
-		FBINFO_HWACCEL_IMAGEBLIT | FBINFO_HWACCEL_FILLRECT |
-		FBINFO_HWACCEL_COPYAREA | FBINFO_MISC_ALWAYS_SETPAR;
-
-/*
- * There are many DisplayLink-based graphics products, all with unique PIDs.
- * So we match on DisplayLink's VID + Vendor-Defined Interface Class (0xff)
- * We also require a match on SubClass (0x00) and Protocol (0x00),
- * which is compatible with all known USB 2.0 era graphics chips and firmware,
- * but allows DisplayLink to increment those for any future incompatible chips
- */
-static const struct usb_device_id id_table[] = {
-	{.idVendor = 0x17e9,
-	 .bInterfaceClass = 0xff,
-	 .bInterfaceSubClass = 0x00,
-	 .bInterfaceProtocol = 0x00,
-	 .match_flags = USB_DEVICE_ID_MATCH_VENDOR |
-		USB_DEVICE_ID_MATCH_INT_CLASS |
-		USB_DEVICE_ID_MATCH_INT_SUBCLASS |
-		USB_DEVICE_ID_MATCH_INT_PROTOCOL,
-	},
-	{},
-};
-MODULE_DEVICE_TABLE(usb, id_table);
-
-/* module options */
-static bool console = true; /* Allow fbcon to open framebuffer */
-static bool fb_defio = true;  /* Detect mmap writes using page faults */
-static bool shadow = true; /* Optionally disable shadow framebuffer */
-static int pixel_limit; /* Optionally force a pixel resolution limit */
-
-struct dlfb_deferred_free {
-	struct list_head list;
-	void *mem;
-};
-
-static int dlfb_realloc_framebuffer(struct dlfb_data *dlfb, struct fb_info *info, u32 new_len);
-
-/* dlfb keeps a list of urbs for efficient bulk transfers */
-static void dlfb_urb_completion(struct urb *urb);
-static struct urb *dlfb_get_urb(struct dlfb_data *dlfb);
-static int dlfb_submit_urb(struct dlfb_data *dlfb, struct urb * urb, size_t len);
-static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size);
-static void dlfb_free_urb_list(struct dlfb_data *dlfb);
-
-/*
- * All DisplayLink bulk operations start with 0xAF, followed by specific code
- * All operations are written to buffers which then later get sent to device
- */
-static char *dlfb_set_register(char *buf, u8 reg, u8 val)
-{
-	*buf++ = 0xAF;
-	*buf++ = 0x20;
-	*buf++ = reg;
-	*buf++ = val;
-	return buf;
-}
-
-static char *dlfb_vidreg_lock(char *buf)
-{
-	return dlfb_set_register(buf, 0xFF, 0x00);
-}
-
-static char *dlfb_vidreg_unlock(char *buf)
-{
-	return dlfb_set_register(buf, 0xFF, 0xFF);
-}
-
-/*
- * Map FB_BLANK_* to DisplayLink register
- * DLReg FB_BLANK_*
- * ----- -----------------------------
- *  0x00 FB_BLANK_UNBLANK (0)
- *  0x01 FB_BLANK (1)
- *  0x03 FB_BLANK_VSYNC_SUSPEND (2)
- *  0x05 FB_BLANK_HSYNC_SUSPEND (3)
- *  0x07 FB_BLANK_POWERDOWN (4) Note: requires modeset to come back
- */
-static char *dlfb_blanking(char *buf, int fb_blank)
-{
-	u8 reg;
-
-	switch (fb_blank) {
-	case FB_BLANK_POWERDOWN:
-		reg = 0x07;
-		break;
-	case FB_BLANK_HSYNC_SUSPEND:
-		reg = 0x05;
-		break;
-	case FB_BLANK_VSYNC_SUSPEND:
-		reg = 0x03;
-		break;
-	case FB_BLANK_NORMAL:
-		reg = 0x01;
-		break;
-	default:
-		reg = 0x00;
-	}
-
-	buf = dlfb_set_register(buf, 0x1F, reg);
-
-	return buf;
-}
-
-static char *dlfb_set_color_depth(char *buf, u8 selection)
-{
-	return dlfb_set_register(buf, 0x00, selection);
-}
-
-static char *dlfb_set_base16bpp(char *wrptr, u32 base)
-{
-	/* the base pointer is 16 bits wide, 0x20 is hi byte. */
-	wrptr = dlfb_set_register(wrptr, 0x20, base >> 16);
-	wrptr = dlfb_set_register(wrptr, 0x21, base >> 8);
-	return dlfb_set_register(wrptr, 0x22, base);
-}
-
-/*
- * DisplayLink HW has separate 16bpp and 8bpp framebuffers.
- * In 24bpp modes, the low 323 RGB bits go in the 8bpp framebuffer
- */
-static char *dlfb_set_base8bpp(char *wrptr, u32 base)
-{
-	wrptr = dlfb_set_register(wrptr, 0x26, base >> 16);
-	wrptr = dlfb_set_register(wrptr, 0x27, base >> 8);
-	return dlfb_set_register(wrptr, 0x28, base);
-}
-
-static char *dlfb_set_register_16(char *wrptr, u8 reg, u16 value)
-{
-	wrptr = dlfb_set_register(wrptr, reg, value >> 8);
-	return dlfb_set_register(wrptr, reg+1, value);
-}
-
-/*
- * This is kind of weird because the controller takes some
- * register values in a different byte order than other registers.
- */
-static char *dlfb_set_register_16be(char *wrptr, u8 reg, u16 value)
-{
-	wrptr = dlfb_set_register(wrptr, reg, value);
-	return dlfb_set_register(wrptr, reg+1, value >> 8);
-}
-
-/*
- * LFSR is linear feedback shift register. The reason we have this is
- * because the display controller needs to minimize the clock depth of
- * various counters used in the display path. So this code reverses the
- * provided value into the lfsr16 value by counting backwards to get
- * the value that needs to be set in the hardware comparator to get the
- * same actual count. This makes sense once you read above a couple of
- * times and think about it from a hardware perspective.
- */
-static u16 dlfb_lfsr16(u16 actual_count)
-{
-	u32 lv = 0xFFFF; /* This is the lfsr value that the hw starts with */
-
-	while (actual_count--) {
-		lv =	 ((lv << 1) |
-			(((lv >> 15) ^ (lv >> 4) ^ (lv >> 2) ^ (lv >> 1)) & 1))
-			& 0xFFFF;
-	}
-
-	return (u16) lv;
-}
-
-/*
- * This does LFSR conversion on the value that is to be written.
- * See LFSR explanation above for more detail.
- */
-static char *dlfb_set_register_lfsr16(char *wrptr, u8 reg, u16 value)
-{
-	return dlfb_set_register_16(wrptr, reg, dlfb_lfsr16(value));
-}
-
-/*
- * This takes a standard fbdev screeninfo struct and all of its monitor mode
- * details and converts them into the DisplayLink equivalent register commands.
- */
-static char *dlfb_set_vid_cmds(char *wrptr, struct fb_var_screeninfo *var)
-{
-	u16 xds, yds;
-	u16 xde, yde;
-	u16 yec;
-
-	/* x display start */
-	xds = var->left_margin + var->hsync_len;
-	wrptr = dlfb_set_register_lfsr16(wrptr, 0x01, xds);
-	/* x display end */
-	xde = xds + var->xres;
-	wrptr = dlfb_set_register_lfsr16(wrptr, 0x03, xde);
-
-	/* y display start */
-	yds = var->upper_margin + var->vsync_len;
-	wrptr = dlfb_set_register_lfsr16(wrptr, 0x05, yds);
-	/* y display end */
-	yde = yds + var->yres;
-	wrptr = dlfb_set_register_lfsr16(wrptr, 0x07, yde);
-
-	/* x end count is active + blanking - 1 */
-	wrptr = dlfb_set_register_lfsr16(wrptr, 0x09,
-			xde + var->right_margin - 1);
-
-	/* libdlo hardcodes hsync start to 1 */
-	wrptr = dlfb_set_register_lfsr16(wrptr, 0x0B, 1);
-
-	/* hsync end is width of sync pulse + 1 */
-	wrptr = dlfb_set_register_lfsr16(wrptr, 0x0D, var->hsync_len + 1);
-
-	/* hpixels is active pixels */
-	wrptr = dlfb_set_register_16(wrptr, 0x0F, var->xres);
-
-	/* yendcount is vertical active + vertical blanking */
-	yec = var->yres + var->upper_margin + var->lower_margin +
-			var->vsync_len;
-	wrptr = dlfb_set_register_lfsr16(wrptr, 0x11, yec);
-
-	/* libdlo hardcodes vsync start to 0 */
-	wrptr = dlfb_set_register_lfsr16(wrptr, 0x13, 0);
-
-	/* vsync end is width of vsync pulse */
-	wrptr = dlfb_set_register_lfsr16(wrptr, 0x15, var->vsync_len);
-
-	/* vpixels is active pixels */
-	wrptr = dlfb_set_register_16(wrptr, 0x17, var->yres);
-
-	/* convert picoseconds to 5kHz multiple for pclk5k = x * 1E12/5k */
-	wrptr = dlfb_set_register_16be(wrptr, 0x1B,
-			200*1000*1000/var->pixclock);
-
-	return wrptr;
-}
-
-/*
- * This takes a standard fbdev screeninfo struct that was fetched or prepared
- * and then generates the appropriate command sequence that then drives the
- * display controller.
- */
-static int dlfb_set_video_mode(struct dlfb_data *dlfb,
-				struct fb_var_screeninfo *var)
-{
-	char *buf;
-	char *wrptr;
-	int retval;
-	int writesize;
-	struct urb *urb;
-
-	if (!atomic_read(&dlfb->usb_active))
-		return -EPERM;
-
-	urb = dlfb_get_urb(dlfb);
-	if (!urb)
-		return -ENOMEM;
-
-	buf = (char *) urb->transfer_buffer;
-
-	/*
-	* This first section has to do with setting the base address on the
-	* controller * associated with the display. There are 2 base
-	* pointers, currently, we only * use the 16 bpp segment.
-	*/
-	wrptr = dlfb_vidreg_lock(buf);
-	wrptr = dlfb_set_color_depth(wrptr, 0x00);
-	/* set base for 16bpp segment to 0 */
-	wrptr = dlfb_set_base16bpp(wrptr, 0);
-	/* set base for 8bpp segment to end of fb */
-	wrptr = dlfb_set_base8bpp(wrptr, dlfb->info->fix.smem_len);
-
-	wrptr = dlfb_set_vid_cmds(wrptr, var);
-	wrptr = dlfb_blanking(wrptr, FB_BLANK_UNBLANK);
-	wrptr = dlfb_vidreg_unlock(wrptr);
-
-	writesize = wrptr - buf;
-
-	retval = dlfb_submit_urb(dlfb, urb, writesize);
-
-	dlfb->blank_mode = FB_BLANK_UNBLANK;
-
-	return retval;
-}
-
-static int dlfb_ops_mmap(struct fb_info *info, struct vm_area_struct *vma)
-{
-	unsigned long start = vma->vm_start;
-	unsigned long size = vma->vm_end - vma->vm_start;
-	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
-	unsigned long page, pos;
-
-	if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
-		return -EINVAL;
-	if (size > info->fix.smem_len)
-		return -EINVAL;
-	if (offset > info->fix.smem_len - size)
-		return -EINVAL;
-
-	pos = (unsigned long)info->fix.smem_start + offset;
-
-	dev_dbg(info->dev, "mmap() framebuffer addr:%lu size:%lu\n",
-		pos, size);
-
-	while (size > 0) {
-		page = vmalloc_to_pfn((void *)pos);
-		if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
-			return -EAGAIN;
-
-		start += PAGE_SIZE;
-		pos += PAGE_SIZE;
-		if (size > PAGE_SIZE)
-			size -= PAGE_SIZE;
-		else
-			size = 0;
-	}
-
-	return 0;
-}
-
-/*
- * Trims identical data from front and back of line
- * Sets new front buffer address and width
- * And returns byte count of identical pixels
- * Assumes CPU natural alignment (unsigned long)
- * for back and front buffer ptrs and width
- */
-static int dlfb_trim_hline(const u8 *bback, const u8 **bfront, int *width_bytes)
-{
-	int j, k;
-	const unsigned long *back = (const unsigned long *) bback;
-	const unsigned long *front = (const unsigned long *) *bfront;
-	const int width = *width_bytes / sizeof(unsigned long);
-	int identical = width;
-	int start = width;
-	int end = width;
-
-	for (j = 0; j < width; j++) {
-		if (back[j] != front[j]) {
-			start = j;
-			break;
-		}
-	}
-
-	for (k = width - 1; k > j; k--) {
-		if (back[k] != front[k]) {
-			end = k+1;
-			break;
-		}
-	}
-
-	identical = start + (width - end);
-	*bfront = (u8 *) &front[start];
-	*width_bytes = (end - start) * sizeof(unsigned long);
-
-	return identical * sizeof(unsigned long);
-}
-
-/*
- * Render a command stream for an encoded horizontal line segment of pixels.
- *
- * A command buffer holds several commands.
- * It always begins with a fresh command header
- * (the protocol doesn't require this, but we enforce it to allow
- * multiple buffers to be potentially encoded and sent in parallel).
- * A single command encodes one contiguous horizontal line of pixels
- *
- * The function relies on the client to do all allocation, so that
- * rendering can be done directly to output buffers (e.g. USB URBs).
- * The function fills the supplied command buffer, providing information
- * on where it left off, so the client may call in again with additional
- * buffers if the line will take several buffers to complete.
- *
- * A single command can transmit a maximum of 256 pixels,
- * regardless of the compression ratio (protocol design limit).
- * To the hardware, 0 for a size byte means 256
- *
- * Rather than 256 pixel commands which are either rl or raw encoded,
- * the rlx command simply assumes alternating raw and rl spans within one cmd.
- * This has a slightly larger header overhead, but produces more even results.
- * It also processes all data (read and write) in a single pass.
- * Performance benchmarks of common cases show it having just slightly better
- * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
- * But for very rl friendly data, will compress not quite as well.
- */
-static void dlfb_compress_hline(
-	const uint16_t **pixel_start_ptr,
-	const uint16_t *const pixel_end,
-	uint32_t *device_address_ptr,
-	uint8_t **command_buffer_ptr,
-	const uint8_t *const cmd_buffer_end,
-	unsigned long back_buffer_offset,
-	int *ident_ptr)
-{
-	const uint16_t *pixel = *pixel_start_ptr;
-	uint32_t dev_addr  = *device_address_ptr;
-	uint8_t *cmd = *command_buffer_ptr;
-
-	while ((pixel_end > pixel) &&
-	       (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
-		uint8_t *raw_pixels_count_byte = NULL;
-		uint8_t *cmd_pixels_count_byte = NULL;
-		const uint16_t *raw_pixel_start = NULL;
-		const uint16_t *cmd_pixel_start, *cmd_pixel_end = NULL;
-
-		if (back_buffer_offset &&
-		    *pixel == *(u16 *)((u8 *)pixel + back_buffer_offset)) {
-			pixel++;
-			dev_addr += BPP;
-			(*ident_ptr)++;
-			continue;
-		}
-
-		*cmd++ = 0xAF;
-		*cmd++ = 0x6B;
-		*cmd++ = dev_addr >> 16;
-		*cmd++ = dev_addr >> 8;
-		*cmd++ = dev_addr;
-
-		cmd_pixels_count_byte = cmd++; /*  we'll know this later */
-		cmd_pixel_start = pixel;
-
-		raw_pixels_count_byte = cmd++; /*  we'll know this later */
-		raw_pixel_start = pixel;
-
-		cmd_pixel_end = pixel + min3(MAX_CMD_PIXELS + 1UL,
-					(unsigned long)(pixel_end - pixel),
-					(unsigned long)(cmd_buffer_end - 1 - cmd) / BPP);
-
-		if (back_buffer_offset) {
-			/* note: the framebuffer may change under us, so we must test for underflow */
-			while (cmd_pixel_end - 1 > pixel &&
-			       *(cmd_pixel_end - 1) == *(u16 *)((u8 *)(cmd_pixel_end - 1) + back_buffer_offset))
-				cmd_pixel_end--;
-		}
-
-		while (pixel < cmd_pixel_end) {
-			const uint16_t * const repeating_pixel = pixel;
-			u16 pixel_value = *pixel;
-
-			put_unaligned_be16(pixel_value, cmd);
-			if (back_buffer_offset)
-				*(u16 *)((u8 *)pixel + back_buffer_offset) = pixel_value;
-			cmd += 2;
-			pixel++;
-
-			if (unlikely((pixel < cmd_pixel_end) &&
-				     (*pixel == pixel_value))) {
-				/* go back and fill in raw pixel count */
-				*raw_pixels_count_byte = ((repeating_pixel -
-						raw_pixel_start) + 1) & 0xFF;
-
-				do {
-					if (back_buffer_offset)
-						*(u16 *)((u8 *)pixel + back_buffer_offset) = pixel_value;
-					pixel++;
-				} while ((pixel < cmd_pixel_end) &&
-					 (*pixel == pixel_value));
-
-				/* immediately after raw data is repeat byte */
-				*cmd++ = ((pixel - repeating_pixel) - 1) & 0xFF;
-
-				/* Then start another raw pixel span */
-				raw_pixel_start = pixel;
-				raw_pixels_count_byte = cmd++;
-			}
-		}
-
-		if (pixel > raw_pixel_start) {
-			/* finalize last RAW span */
-			*raw_pixels_count_byte = (pixel-raw_pixel_start) & 0xFF;
-		} else {
-			/* undo unused byte */
-			cmd--;
-		}
-
-		*cmd_pixels_count_byte = (pixel - cmd_pixel_start) & 0xFF;
-		dev_addr += (u8 *)pixel - (u8 *)cmd_pixel_start;
-	}
-
-	if (cmd_buffer_end - MIN_RLX_CMD_BYTES <= cmd) {
-		/* Fill leftover bytes with no-ops */
-		if (cmd_buffer_end > cmd)
-			memset(cmd, 0xAF, cmd_buffer_end - cmd);
-		cmd = (uint8_t *) cmd_buffer_end;
-	}
-
-	*command_buffer_ptr = cmd;
-	*pixel_start_ptr = pixel;
-	*device_address_ptr = dev_addr;
-}
-
-/*
- * There are 3 copies of every pixel: The front buffer that the fbdev
- * client renders to, the actual framebuffer across the USB bus in hardware
- * (that we can only write to, slowly, and can never read), and (optionally)
- * our shadow copy that tracks what's been sent to that hardware buffer.
- */
-static int dlfb_render_hline(struct dlfb_data *dlfb, struct urb **urb_ptr,
-			      const char *front, char **urb_buf_ptr,
-			      u32 byte_offset, u32 byte_width,
-			      int *ident_ptr, int *sent_ptr)
-{
-	const u8 *line_start, *line_end, *next_pixel;
-	u32 dev_addr = dlfb->base16 + byte_offset;
-	struct urb *urb = *urb_ptr;
-	u8 *cmd = *urb_buf_ptr;
-	u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
-	unsigned long back_buffer_offset = 0;
-
-	line_start = (u8 *) (front + byte_offset);
-	next_pixel = line_start;
-	line_end = next_pixel + byte_width;
-
-	if (dlfb->backing_buffer) {
-		int offset;
-		const u8 *back_start = (u8 *) (dlfb->backing_buffer
-						+ byte_offset);
-
-		back_buffer_offset = (unsigned long)back_start - (unsigned long)line_start;
-
-		*ident_ptr += dlfb_trim_hline(back_start, &next_pixel,
-			&byte_width);
-
-		offset = next_pixel - line_start;
-		line_end = next_pixel + byte_width;
-		dev_addr += offset;
-		back_start += offset;
-		line_start += offset;
-	}
-
-	while (next_pixel < line_end) {
-
-		dlfb_compress_hline((const uint16_t **) &next_pixel,
-			     (const uint16_t *) line_end, &dev_addr,
-			(u8 **) &cmd, (u8 *) cmd_end, back_buffer_offset,
-			ident_ptr);
-
-		if (cmd >= cmd_end) {
-			int len = cmd - (u8 *) urb->transfer_buffer;
-			if (dlfb_submit_urb(dlfb, urb, len))
-				return 1; /* lost pixels is set */
-			*sent_ptr += len;
-			urb = dlfb_get_urb(dlfb);
-			if (!urb)
-				return 1; /* lost_pixels is set */
-			*urb_ptr = urb;
-			cmd = urb->transfer_buffer;
-			cmd_end = &cmd[urb->transfer_buffer_length];
-		}
-	}
-
-	*urb_buf_ptr = cmd;
-
-	return 0;
-}
-
-static int dlfb_handle_damage(struct dlfb_data *dlfb, int x, int y, int width, int height)
-{
-	int i, ret;
-	char *cmd;
-	cycles_t start_cycles, end_cycles;
-	int bytes_sent = 0;
-	int bytes_identical = 0;
-	struct urb *urb;
-	int aligned_x;
-
-	start_cycles = get_cycles();
-
-	mutex_lock(&dlfb->render_mutex);
-
-	aligned_x = DL_ALIGN_DOWN(x, sizeof(unsigned long));
-	width = DL_ALIGN_UP(width + (x-aligned_x), sizeof(unsigned long));
-	x = aligned_x;
-
-	if ((width <= 0) ||
-	    (x + width > dlfb->info->var.xres) ||
-	    (y + height > dlfb->info->var.yres)) {
-		ret = -EINVAL;
-		goto unlock_ret;
-	}
-
-	if (!atomic_read(&dlfb->usb_active)) {
-		ret = 0;
-		goto unlock_ret;
-	}
-
-	urb = dlfb_get_urb(dlfb);
-	if (!urb) {
-		ret = 0;
-		goto unlock_ret;
-	}
-	cmd = urb->transfer_buffer;
-
-	for (i = y; i < y + height ; i++) {
-		const int line_offset = dlfb->info->fix.line_length * i;
-		const int byte_offset = line_offset + (x * BPP);
-
-		if (dlfb_render_hline(dlfb, &urb,
-				      (char *) dlfb->info->fix.smem_start,
-				      &cmd, byte_offset, width * BPP,
-				      &bytes_identical, &bytes_sent))
-			goto error;
-	}
-
-	if (cmd > (char *) urb->transfer_buffer) {
-		int len;
-		if (cmd < (char *) urb->transfer_buffer + urb->transfer_buffer_length)
-			*cmd++ = 0xAF;
-		/* Send partial buffer remaining before exiting */
-		len = cmd - (char *) urb->transfer_buffer;
-		dlfb_submit_urb(dlfb, urb, len);
-		bytes_sent += len;
-	} else
-		dlfb_urb_completion(urb);
-
-error:
-	atomic_add(bytes_sent, &dlfb->bytes_sent);
-	atomic_add(bytes_identical, &dlfb->bytes_identical);
-	atomic_add(width*height*2, &dlfb->bytes_rendered);
-	end_cycles = get_cycles();
-	atomic_add(((unsigned int) ((end_cycles - start_cycles)
-		    >> 10)), /* Kcycles */
-		   &dlfb->cpu_kcycles_used);
-
-	ret = 0;
-
-unlock_ret:
-	mutex_unlock(&dlfb->render_mutex);
-	return ret;
-}
-
-static void dlfb_init_damage(struct dlfb_data *dlfb)
-{
-	dlfb->damage_x = INT_MAX;
-	dlfb->damage_x2 = 0;
-	dlfb->damage_y = INT_MAX;
-	dlfb->damage_y2 = 0;
-}
-
-static void dlfb_damage_work(struct work_struct *w)
-{
-	struct dlfb_data *dlfb = container_of(w, struct dlfb_data, damage_work);
-	int x, x2, y, y2;
-
-	spin_lock_irq(&dlfb->damage_lock);
-	x = dlfb->damage_x;
-	x2 = dlfb->damage_x2;
-	y = dlfb->damage_y;
-	y2 = dlfb->damage_y2;
-	dlfb_init_damage(dlfb);
-	spin_unlock_irq(&dlfb->damage_lock);
-
-	if (x < x2 && y < y2)
-		dlfb_handle_damage(dlfb, x, y, x2 - x, y2 - y);
-}
-
-static void dlfb_offload_damage(struct dlfb_data *dlfb, int x, int y, int width, int height)
-{
-	unsigned long flags;
-	int x2 = x + width;
-	int y2 = y + height;
-
-	if (x >= x2 || y >= y2)
-		return;
-
-	spin_lock_irqsave(&dlfb->damage_lock, flags);
-	dlfb->damage_x = min(x, dlfb->damage_x);
-	dlfb->damage_x2 = max(x2, dlfb->damage_x2);
-	dlfb->damage_y = min(y, dlfb->damage_y);
-	dlfb->damage_y2 = max(y2, dlfb->damage_y2);
-	spin_unlock_irqrestore(&dlfb->damage_lock, flags);
-
-	schedule_work(&dlfb->damage_work);
-}
-
-/*
- * Path triggered by usermode clients who write to filesystem
- * e.g. cat filename > /dev/fb1
- * Not used by X Windows or text-mode console. But useful for testing.
- * Slow because of extra copy and we must assume all pixels dirty.
- */
-static ssize_t dlfb_ops_write(struct fb_info *info, const char __user *buf,
-			  size_t count, loff_t *ppos)
-{
-	ssize_t result;
-	struct dlfb_data *dlfb = info->par;
-	u32 offset = (u32) *ppos;
-
-	result = fb_sys_write(info, buf, count, ppos);
-
-	if (result > 0) {
-		int start = max((int)(offset / info->fix.line_length), 0);
-		int lines = min((u32)((result / info->fix.line_length) + 1),
-				(u32)info->var.yres);
-
-		dlfb_handle_damage(dlfb, 0, start, info->var.xres,
-			lines);
-	}
-
-	return result;
-}
-
-/* hardware has native COPY command (see libdlo), but not worth it for fbcon */
-static void dlfb_ops_copyarea(struct fb_info *info,
-				const struct fb_copyarea *area)
-{
-
-	struct dlfb_data *dlfb = info->par;
-
-	sys_copyarea(info, area);
-
-	dlfb_offload_damage(dlfb, area->dx, area->dy,
-			area->width, area->height);
-}
-
-static void dlfb_ops_imageblit(struct fb_info *info,
-				const struct fb_image *image)
-{
-	struct dlfb_data *dlfb = info->par;
-
-	sys_imageblit(info, image);
-
-	dlfb_offload_damage(dlfb, image->dx, image->dy,
-			image->width, image->height);
-}
-
-static void dlfb_ops_fillrect(struct fb_info *info,
-			  const struct fb_fillrect *rect)
-{
-	struct dlfb_data *dlfb = info->par;
-
-	sys_fillrect(info, rect);
-
-	dlfb_offload_damage(dlfb, rect->dx, rect->dy, rect->width,
-			      rect->height);
-}
-
-/*
- * NOTE: fb_defio.c is holding info->fbdefio.mutex
- *   Touching ANY framebuffer memory that triggers a page fault
- *   in fb_defio will cause a deadlock, when it also tries to
- *   grab the same mutex.
- */
-static void dlfb_dpy_deferred_io(struct fb_info *info,
-				struct list_head *pagelist)
-{
-	struct page *cur;
-	struct fb_deferred_io *fbdefio = info->fbdefio;
-	struct dlfb_data *dlfb = info->par;
-	struct urb *urb;
-	char *cmd;
-	cycles_t start_cycles, end_cycles;
-	int bytes_sent = 0;
-	int bytes_identical = 0;
-	int bytes_rendered = 0;
-
-	mutex_lock(&dlfb->render_mutex);
-
-	if (!fb_defio)
-		goto unlock_ret;
-
-	if (!atomic_read(&dlfb->usb_active))
-		goto unlock_ret;
-
-	start_cycles = get_cycles();
-
-	urb = dlfb_get_urb(dlfb);
-	if (!urb)
-		goto unlock_ret;
-
-	cmd = urb->transfer_buffer;
-
-	/* walk the written page list and render each to device */
-	list_for_each_entry(cur, &fbdefio->pagelist, lru) {
-
-		if (dlfb_render_hline(dlfb, &urb, (char *) info->fix.smem_start,
-				  &cmd, cur->index << PAGE_SHIFT,
-				  PAGE_SIZE, &bytes_identical, &bytes_sent))
-			goto error;
-		bytes_rendered += PAGE_SIZE;
-	}
-
-	if (cmd > (char *) urb->transfer_buffer) {
-		int len;
-		if (cmd < (char *) urb->transfer_buffer + urb->transfer_buffer_length)
-			*cmd++ = 0xAF;
-		/* Send partial buffer remaining before exiting */
-		len = cmd - (char *) urb->transfer_buffer;
-		dlfb_submit_urb(dlfb, urb, len);
-		bytes_sent += len;
-	} else
-		dlfb_urb_completion(urb);
-
-error:
-	atomic_add(bytes_sent, &dlfb->bytes_sent);
-	atomic_add(bytes_identical, &dlfb->bytes_identical);
-	atomic_add(bytes_rendered, &dlfb->bytes_rendered);
-	end_cycles = get_cycles();
-	atomic_add(((unsigned int) ((end_cycles - start_cycles)
-		    >> 10)), /* Kcycles */
-		   &dlfb->cpu_kcycles_used);
-unlock_ret:
-	mutex_unlock(&dlfb->render_mutex);
-}
-
-static int dlfb_get_edid(struct dlfb_data *dlfb, char *edid, int len)
-{
-	int i, ret;
-	char *rbuf;
-
-	rbuf = kmalloc(2, GFP_KERNEL);
-	if (!rbuf)
-		return 0;
-
-	for (i = 0; i < len; i++) {
-		ret = usb_control_msg(dlfb->udev,
-				      usb_rcvctrlpipe(dlfb->udev, 0), 0x02,
-				      (0x80 | (0x02 << 5)), i << 8, 0xA1,
-				      rbuf, 2, USB_CTRL_GET_TIMEOUT);
-		if (ret < 2) {
-			dev_err(&dlfb->udev->dev,
-				"Read EDID byte %d failed: %d\n", i, ret);
-			i--;
-			break;
-		}
-		edid[i] = rbuf[1];
-	}
-
-	kfree(rbuf);
-
-	return i;
-}
-
-static int dlfb_ops_ioctl(struct fb_info *info, unsigned int cmd,
-				unsigned long arg)
-{
-
-	struct dlfb_data *dlfb = info->par;
-
-	if (!atomic_read(&dlfb->usb_active))
-		return 0;
-
-	/* TODO: Update X server to get this from sysfs instead */
-	if (cmd == DLFB_IOCTL_RETURN_EDID) {
-		void __user *edid = (void __user *)arg;
-		if (copy_to_user(edid, dlfb->edid, dlfb->edid_size))
-			return -EFAULT;
-		return 0;
-	}
-
-	/* TODO: Help propose a standard fb.h ioctl to report mmap damage */
-	if (cmd == DLFB_IOCTL_REPORT_DAMAGE) {
-		struct dloarea area;
-
-		if (copy_from_user(&area, (void __user *)arg,
-				  sizeof(struct dloarea)))
-			return -EFAULT;
-
-		/*
-		 * If we have a damage-aware client, turn fb_defio "off"
-		 * To avoid perf imact of unnecessary page fault handling.
-		 * Done by resetting the delay for this fb_info to a very
-		 * long period. Pages will become writable and stay that way.
-		 * Reset to normal value when all clients have closed this fb.
-		 */
-		if (info->fbdefio)
-			info->fbdefio->delay = DL_DEFIO_WRITE_DISABLE;
-
-		if (area.x < 0)
-			area.x = 0;
-
-		if (area.x > info->var.xres)
-			area.x = info->var.xres;
-
-		if (area.y < 0)
-			area.y = 0;
-
-		if (area.y > info->var.yres)
-			area.y = info->var.yres;
-
-		dlfb_handle_damage(dlfb, area.x, area.y, area.w, area.h);
-	}
-
-	return 0;
-}
-
-/* taken from vesafb */
-static int
-dlfb_ops_setcolreg(unsigned regno, unsigned red, unsigned green,
-	       unsigned blue, unsigned transp, struct fb_info *info)
-{
-	int err = 0;
-
-	if (regno >= info->cmap.len)
-		return 1;
-
-	if (regno < 16) {
-		if (info->var.red.offset == 10) {
-			/* 1:5:5:5 */
-			((u32 *) (info->pseudo_palette))[regno] =
-			    ((red & 0xf800) >> 1) |
-			    ((green & 0xf800) >> 6) | ((blue & 0xf800) >> 11);
-		} else {
-			/* 0:5:6:5 */
-			((u32 *) (info->pseudo_palette))[regno] =
-			    ((red & 0xf800)) |
-			    ((green & 0xfc00) >> 5) | ((blue & 0xf800) >> 11);
-		}
-	}
-
-	return err;
-}
-
-/*
- * It's common for several clients to have framebuffer open simultaneously.
- * e.g. both fbcon and X. Makes things interesting.
- * Assumes caller is holding info->lock (for open and release at least)
- */
-static int dlfb_ops_open(struct fb_info *info, int user)
-{
-	struct dlfb_data *dlfb = info->par;
-
-	/*
-	 * fbcon aggressively connects to first framebuffer it finds,
-	 * preventing other clients (X) from working properly. Usually
-	 * not what the user wants. Fail by default with option to enable.
-	 */
-	if ((user == 0) && (!console))
-		return -EBUSY;
-
-	/* If the USB device is gone, we don't accept new opens */
-	if (dlfb->virtualized)
-		return -ENODEV;
-
-	dlfb->fb_count++;
-
-	if (fb_defio && (info->fbdefio == NULL)) {
-		/* enable defio at last moment if not disabled by client */
-
-		struct fb_deferred_io *fbdefio;
-
-		fbdefio = kzalloc(sizeof(struct fb_deferred_io), GFP_KERNEL);
-
-		if (fbdefio) {
-			fbdefio->delay = DL_DEFIO_WRITE_DELAY;
-			fbdefio->deferred_io = dlfb_dpy_deferred_io;
-		}
-
-		info->fbdefio = fbdefio;
-		fb_deferred_io_init(info);
-	}
-
-	dev_dbg(info->dev, "open, user=%d fb_info=%p count=%d\n",
-		user, info, dlfb->fb_count);
-
-	return 0;
-}
-
-static void dlfb_ops_destroy(struct fb_info *info)
-{
-	struct dlfb_data *dlfb = info->par;
-
-	cancel_work_sync(&dlfb->damage_work);
-
-	mutex_destroy(&dlfb->render_mutex);
-
-	if (info->cmap.len != 0)
-		fb_dealloc_cmap(&info->cmap);
-	if (info->monspecs.modedb)
-		fb_destroy_modedb(info->monspecs.modedb);
-	vfree(info->screen_base);
-
-	fb_destroy_modelist(&info->modelist);
-
-	while (!list_empty(&dlfb->deferred_free)) {
-		struct dlfb_deferred_free *d = list_entry(dlfb->deferred_free.next, struct dlfb_deferred_free, list);
-		list_del(&d->list);
-		vfree(d->mem);
-		kfree(d);
-	}
-	vfree(dlfb->backing_buffer);
-	kfree(dlfb->edid);
-	usb_put_dev(dlfb->udev);
-	kfree(dlfb);
-
-	/* Assume info structure is freed after this point */
-	framebuffer_release(info);
-}
-
-/*
- * Assumes caller is holding info->lock mutex (for open and release at least)
- */
-static int dlfb_ops_release(struct fb_info *info, int user)
-{
-	struct dlfb_data *dlfb = info->par;
-
-	dlfb->fb_count--;
-
-	if ((dlfb->fb_count == 0) && (info->fbdefio)) {
-		fb_deferred_io_cleanup(info);
-		kfree(info->fbdefio);
-		info->fbdefio = NULL;
-	}
-
-	dev_dbg(info->dev, "release, user=%d count=%d\n", user, dlfb->fb_count);
-
-	return 0;
-}
-
-/*
- * Check whether a video mode is supported by the DisplayLink chip
- * We start from monitor's modes, so don't need to filter that here
- */
-static int dlfb_is_valid_mode(struct fb_videomode *mode, struct dlfb_data *dlfb)
-{
-	if (mode->xres * mode->yres > dlfb->sku_pixel_limit)
-		return 0;
-
-	return 1;
-}
-
-static void dlfb_var_color_format(struct fb_var_screeninfo *var)
-{
-	const struct fb_bitfield red = { 11, 5, 0 };
-	const struct fb_bitfield green = { 5, 6, 0 };
-	const struct fb_bitfield blue = { 0, 5, 0 };
-
-	var->bits_per_pixel = 16;
-	var->red = red;
-	var->green = green;
-	var->blue = blue;
-}
-
-static int dlfb_ops_check_var(struct fb_var_screeninfo *var,
-				struct fb_info *info)
-{
-	struct fb_videomode mode;
-	struct dlfb_data *dlfb = info->par;
-
-	/* set device-specific elements of var unrelated to mode */
-	dlfb_var_color_format(var);
-
-	fb_var_to_videomode(&mode, var);
-
-	if (!dlfb_is_valid_mode(&mode, dlfb))
-		return -EINVAL;
-
-	return 0;
-}
-
-static int dlfb_ops_set_par(struct fb_info *info)
-{
-	struct dlfb_data *dlfb = info->par;
-	int result;
-	u16 *pix_framebuffer;
-	int i;
-	struct fb_var_screeninfo fvs;
-	u32 line_length = info->var.xres * (info->var.bits_per_pixel / 8);
-
-	/* clear the activate field because it causes spurious miscompares */
-	fvs = info->var;
-	fvs.activate = 0;
-	fvs.vmode &= ~FB_VMODE_SMOOTH_XPAN;
-
-	if (!memcmp(&dlfb->current_mode, &fvs, sizeof(struct fb_var_screeninfo)))
-		return 0;
-
-	result = dlfb_realloc_framebuffer(dlfb, info, info->var.yres * line_length);
-	if (result)
-		return result;
-
-	result = dlfb_set_video_mode(dlfb, &info->var);
-
-	if (result)
-		return result;
-
-	dlfb->current_mode = fvs;
-	info->fix.line_length = line_length;
-
-	if (dlfb->fb_count == 0) {
-
-		/* paint greenscreen */
-
-		pix_framebuffer = (u16 *) info->screen_base;
-		for (i = 0; i < info->fix.smem_len / 2; i++)
-			pix_framebuffer[i] = 0x37e6;
-	}
-
-	dlfb_handle_damage(dlfb, 0, 0, info->var.xres, info->var.yres);
-
-	return 0;
-}
-
-/* To fonzi the jukebox (e.g. make blanking changes take effect) */
-static char *dlfb_dummy_render(char *buf)
-{
-	*buf++ = 0xAF;
-	*buf++ = 0x6A; /* copy */
-	*buf++ = 0x00; /* from address*/
-	*buf++ = 0x00;
-	*buf++ = 0x00;
-	*buf++ = 0x01; /* one pixel */
-	*buf++ = 0x00; /* to address */
-	*buf++ = 0x00;
-	*buf++ = 0x00;
-	return buf;
-}
-
-/*
- * In order to come back from full DPMS off, we need to set the mode again
- */
-static int dlfb_ops_blank(int blank_mode, struct fb_info *info)
-{
-	struct dlfb_data *dlfb = info->par;
-	char *bufptr;
-	struct urb *urb;
-
-	dev_dbg(info->dev, "blank, mode %d --> %d\n",
-		dlfb->blank_mode, blank_mode);
-
-	if ((dlfb->blank_mode == FB_BLANK_POWERDOWN) &&
-	    (blank_mode != FB_BLANK_POWERDOWN)) {
-
-		/* returning from powerdown requires a fresh modeset */
-		dlfb_set_video_mode(dlfb, &info->var);
-	}
-
-	urb = dlfb_get_urb(dlfb);
-	if (!urb)
-		return 0;
-
-	bufptr = (char *) urb->transfer_buffer;
-	bufptr = dlfb_vidreg_lock(bufptr);
-	bufptr = dlfb_blanking(bufptr, blank_mode);
-	bufptr = dlfb_vidreg_unlock(bufptr);
-
-	/* seems like a render op is needed to have blank change take effect */
-	bufptr = dlfb_dummy_render(bufptr);
-
-	dlfb_submit_urb(dlfb, urb, bufptr -
-			(char *) urb->transfer_buffer);
-
-	dlfb->blank_mode = blank_mode;
-
-	return 0;
-}
-
-static const struct fb_ops dlfb_ops = {
-	.owner = THIS_MODULE,
-	.fb_read = fb_sys_read,
-	.fb_write = dlfb_ops_write,
-	.fb_setcolreg = dlfb_ops_setcolreg,
-	.fb_fillrect = dlfb_ops_fillrect,
-	.fb_copyarea = dlfb_ops_copyarea,
-	.fb_imageblit = dlfb_ops_imageblit,
-	.fb_mmap = dlfb_ops_mmap,
-	.fb_ioctl = dlfb_ops_ioctl,
-	.fb_open = dlfb_ops_open,
-	.fb_release = dlfb_ops_release,
-	.fb_blank = dlfb_ops_blank,
-	.fb_check_var = dlfb_ops_check_var,
-	.fb_set_par = dlfb_ops_set_par,
-	.fb_destroy = dlfb_ops_destroy,
-};
-
-
-static void dlfb_deferred_vfree(struct dlfb_data *dlfb, void *mem)
-{
-	struct dlfb_deferred_free *d = kmalloc(sizeof(struct dlfb_deferred_free), GFP_KERNEL);
-	if (!d)
-		return;
-	d->mem = mem;
-	list_add(&d->list, &dlfb->deferred_free);
-}
-
-/*
- * Assumes &info->lock held by caller
- * Assumes no active clients have framebuffer open
- */
-static int dlfb_realloc_framebuffer(struct dlfb_data *dlfb, struct fb_info *info, u32 new_len)
-{
-	u32 old_len = info->fix.smem_len;
-	const void *old_fb = (const void __force *)info->screen_base;
-	unsigned char *new_fb;
-	unsigned char *new_back = NULL;
-
-	new_len = PAGE_ALIGN(new_len);
-
-	if (new_len > old_len) {
-		/*
-		 * Alloc system memory for virtual framebuffer
-		 */
-		new_fb = vmalloc(new_len);
-		if (!new_fb) {
-			dev_err(info->dev, "Virtual framebuffer alloc failed\n");
-			return -ENOMEM;
-		}
-		memset(new_fb, 0xff, new_len);
-
-		if (info->screen_base) {
-			memcpy(new_fb, old_fb, old_len);
-			dlfb_deferred_vfree(dlfb, (void __force *)info->screen_base);
-		}
-
-		info->screen_base = (char __iomem *)new_fb;
-		info->fix.smem_len = new_len;
-		info->fix.smem_start = (unsigned long) new_fb;
-		info->flags = udlfb_info_flags;
-
-		/*
-		 * Second framebuffer copy to mirror the framebuffer state
-		 * on the physical USB device. We can function without this.
-		 * But with imperfect damage info we may send pixels over USB
-		 * that were, in fact, unchanged - wasting limited USB bandwidth
-		 */
-		if (shadow)
-			new_back = vzalloc(new_len);
-		if (!new_back)
-			dev_info(info->dev,
-				 "No shadow/backing buffer allocated\n");
-		else {
-			dlfb_deferred_vfree(dlfb, dlfb->backing_buffer);
-			dlfb->backing_buffer = new_back;
-		}
-	}
-	return 0;
-}
-
-/*
- * 1) Get EDID from hw, or use sw default
- * 2) Parse into various fb_info structs
- * 3) Allocate virtual framebuffer memory to back highest res mode
- *
- * Parses EDID into three places used by various parts of fbdev:
- * fb_var_screeninfo contains the timing of the monitor's preferred mode
- * fb_info.monspecs is full parsed EDID info, including monspecs.modedb
- * fb_info.modelist is a linked list of all monitor & VESA modes which work
- *
- * If EDID is not readable/valid, then modelist is all VESA modes,
- * monspecs is NULL, and fb_var_screeninfo is set to safe VESA mode
- * Returns 0 if successful
- */
-static int dlfb_setup_modes(struct dlfb_data *dlfb,
-			   struct fb_info *info,
-			   char *default_edid, size_t default_edid_size)
-{
-	char *edid;
-	int i, result = 0, tries = 3;
-	struct device *dev = info->device;
-	struct fb_videomode *mode;
-	const struct fb_videomode *default_vmode = NULL;
-
-	if (info->dev) {
-		/* only use mutex if info has been registered */
-		mutex_lock(&info->lock);
-		/* parent device is used otherwise */
-		dev = info->dev;
-	}
-
-	edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
-	if (!edid) {
-		result = -ENOMEM;
-		goto error;
-	}
-
-	fb_destroy_modelist(&info->modelist);
-	memset(&info->monspecs, 0, sizeof(info->monspecs));
-
-	/*
-	 * Try to (re)read EDID from hardware first
-	 * EDID data may return, but not parse as valid
-	 * Try again a few times, in case of e.g. analog cable noise
-	 */
-	while (tries--) {
-
-		i = dlfb_get_edid(dlfb, edid, EDID_LENGTH);
-
-		if (i >= EDID_LENGTH)
-			fb_edid_to_monspecs(edid, &info->monspecs);
-
-		if (info->monspecs.modedb_len > 0) {
-			dlfb->edid = edid;
-			dlfb->edid_size = i;
-			break;
-		}
-	}
-
-	/* If that fails, use a previously returned EDID if available */
-	if (info->monspecs.modedb_len == 0) {
-		dev_err(dev, "Unable to get valid EDID from device/display\n");
-
-		if (dlfb->edid) {
-			fb_edid_to_monspecs(dlfb->edid, &info->monspecs);
-			if (info->monspecs.modedb_len > 0)
-				dev_err(dev, "Using previously queried EDID\n");
-		}
-	}
-
-	/* If that fails, use the default EDID we were handed */
-	if (info->monspecs.modedb_len == 0) {
-		if (default_edid_size >= EDID_LENGTH) {
-			fb_edid_to_monspecs(default_edid, &info->monspecs);
-			if (info->monspecs.modedb_len > 0) {
-				memcpy(edid, default_edid, default_edid_size);
-				dlfb->edid = edid;
-				dlfb->edid_size = default_edid_size;
-				dev_err(dev, "Using default/backup EDID\n");
-			}
-		}
-	}
-
-	/* If we've got modes, let's pick a best default mode */
-	if (info->monspecs.modedb_len > 0) {
-
-		for (i = 0; i < info->monspecs.modedb_len; i++) {
-			mode = &info->monspecs.modedb[i];
-			if (dlfb_is_valid_mode(mode, dlfb)) {
-				fb_add_videomode(mode, &info->modelist);
-			} else {
-				dev_dbg(dev, "Specified mode %dx%d too big\n",
-					mode->xres, mode->yres);
-				if (i == 0)
-					/* if we've removed top/best mode */
-					info->monspecs.misc
-						&= ~FB_MISC_1ST_DETAIL;
-			}
-		}
-
-		default_vmode = fb_find_best_display(&info->monspecs,
-						     &info->modelist);
-	}
-
-	/* If everything else has failed, fall back to safe default mode */
-	if (default_vmode == NULL) {
-
-		struct fb_videomode fb_vmode = {0};
-
-		/*
-		 * Add the standard VESA modes to our modelist
-		 * Since we don't have EDID, there may be modes that
-		 * overspec monitor and/or are incorrect aspect ratio, etc.
-		 * But at least the user has a chance to choose
-		 */
-		for (i = 0; i < VESA_MODEDB_SIZE; i++) {
-			mode = (struct fb_videomode *)&vesa_modes[i];
-			if (dlfb_is_valid_mode(mode, dlfb))
-				fb_add_videomode(mode, &info->modelist);
-			else
-				dev_dbg(dev, "VESA mode %dx%d too big\n",
-					mode->xres, mode->yres);
-		}
-
-		/*
-		 * default to resolution safe for projectors
-		 * (since they are most common case without EDID)
-		 */
-		fb_vmode.xres = 800;
-		fb_vmode.yres = 600;
-		fb_vmode.refresh = 60;
-		default_vmode = fb_find_nearest_mode(&fb_vmode,
-						     &info->modelist);
-	}
-
-	/* If we have good mode and no active clients*/
-	if ((default_vmode != NULL) && (dlfb->fb_count == 0)) {
-
-		fb_videomode_to_var(&info->var, default_vmode);
-		dlfb_var_color_format(&info->var);
-
-		/*
-		 * with mode size info, we can now alloc our framebuffer.
-		 */
-		memcpy(&info->fix, &dlfb_fix, sizeof(dlfb_fix));
-	} else
-		result = -EINVAL;
-
-error:
-	if (edid && (dlfb->edid != edid))
-		kfree(edid);
-
-	if (info->dev)
-		mutex_unlock(&info->lock);
-
-	return result;
-}
-
-static ssize_t metrics_bytes_rendered_show(struct device *fbdev,
-				   struct device_attribute *a, char *buf) {
-	struct fb_info *fb_info = dev_get_drvdata(fbdev);
-	struct dlfb_data *dlfb = fb_info->par;
-	return snprintf(buf, PAGE_SIZE, "%u\n",
-			atomic_read(&dlfb->bytes_rendered));
-}
-
-static ssize_t metrics_bytes_identical_show(struct device *fbdev,
-				   struct device_attribute *a, char *buf) {
-	struct fb_info *fb_info = dev_get_drvdata(fbdev);
-	struct dlfb_data *dlfb = fb_info->par;
-	return snprintf(buf, PAGE_SIZE, "%u\n",
-			atomic_read(&dlfb->bytes_identical));
-}
-
-static ssize_t metrics_bytes_sent_show(struct device *fbdev,
-				   struct device_attribute *a, char *buf) {
-	struct fb_info *fb_info = dev_get_drvdata(fbdev);
-	struct dlfb_data *dlfb = fb_info->par;
-	return snprintf(buf, PAGE_SIZE, "%u\n",
-			atomic_read(&dlfb->bytes_sent));
-}
-
-static ssize_t metrics_cpu_kcycles_used_show(struct device *fbdev,
-				   struct device_attribute *a, char *buf) {
-	struct fb_info *fb_info = dev_get_drvdata(fbdev);
-	struct dlfb_data *dlfb = fb_info->par;
-	return snprintf(buf, PAGE_SIZE, "%u\n",
-			atomic_read(&dlfb->cpu_kcycles_used));
-}
-
-static ssize_t edid_show(
-			struct file *filp,
-			struct kobject *kobj, struct bin_attribute *a,
-			 char *buf, loff_t off, size_t count) {
-	struct device *fbdev = kobj_to_dev(kobj);
-	struct fb_info *fb_info = dev_get_drvdata(fbdev);
-	struct dlfb_data *dlfb = fb_info->par;
-
-	if (dlfb->edid == NULL)
-		return 0;
-
-	if ((off >= dlfb->edid_size) || (count > dlfb->edid_size))
-		return 0;
-
-	if (off + count > dlfb->edid_size)
-		count = dlfb->edid_size - off;
-
-	memcpy(buf, dlfb->edid, count);
-
-	return count;
-}
-
-static ssize_t edid_store(
-			struct file *filp,
-			struct kobject *kobj, struct bin_attribute *a,
-			char *src, loff_t src_off, size_t src_size) {
-	struct device *fbdev = kobj_to_dev(kobj);
-	struct fb_info *fb_info = dev_get_drvdata(fbdev);
-	struct dlfb_data *dlfb = fb_info->par;
-	int ret;
-
-	/* We only support write of entire EDID at once, no offset*/
-	if ((src_size != EDID_LENGTH) || (src_off != 0))
-		return -EINVAL;
-
-	ret = dlfb_setup_modes(dlfb, fb_info, src, src_size);
-	if (ret)
-		return ret;
-
-	if (!dlfb->edid || memcmp(src, dlfb->edid, src_size))
-		return -EINVAL;
-
-	ret = dlfb_ops_set_par(fb_info);
-	if (ret)
-		return ret;
-
-	return src_size;
-}
-
-static ssize_t metrics_reset_store(struct device *fbdev,
-			   struct device_attribute *attr,
-			   const char *buf, size_t count)
-{
-	struct fb_info *fb_info = dev_get_drvdata(fbdev);
-	struct dlfb_data *dlfb = fb_info->par;
-
-	atomic_set(&dlfb->bytes_rendered, 0);
-	atomic_set(&dlfb->bytes_identical, 0);
-	atomic_set(&dlfb->bytes_sent, 0);
-	atomic_set(&dlfb->cpu_kcycles_used, 0);
-
-	return count;
-}
-
-static const struct bin_attribute edid_attr = {
-	.attr.name = "edid",
-	.attr.mode = 0666,
-	.size = EDID_LENGTH,
-	.read = edid_show,
-	.write = edid_store
-};
-
-static const struct device_attribute fb_device_attrs[] = {
-	__ATTR_RO(metrics_bytes_rendered),
-	__ATTR_RO(metrics_bytes_identical),
-	__ATTR_RO(metrics_bytes_sent),
-	__ATTR_RO(metrics_cpu_kcycles_used),
-	__ATTR(metrics_reset, S_IWUSR, NULL, metrics_reset_store),
-};
-
-/*
- * This is necessary before we can communicate with the display controller.
- */
-static int dlfb_select_std_channel(struct dlfb_data *dlfb)
-{
-	int ret;
-	void *buf;
-	static const u8 set_def_chn[] = {
-				0x57, 0xCD, 0xDC, 0xA7,
-				0x1C, 0x88, 0x5E, 0x15,
-				0x60, 0xFE, 0xC6, 0x97,
-				0x16, 0x3D, 0x47, 0xF2  };
-
-	buf = kmemdup(set_def_chn, sizeof(set_def_chn), GFP_KERNEL);
-
-	if (!buf)
-		return -ENOMEM;
-
-	ret = usb_control_msg(dlfb->udev, usb_sndctrlpipe(dlfb->udev, 0),
-			NR_USB_REQUEST_CHANNEL,
-			(USB_DIR_OUT | USB_TYPE_VENDOR), 0, 0,
-			buf, sizeof(set_def_chn), USB_CTRL_SET_TIMEOUT);
-
-	kfree(buf);
-
-	return ret;
-}
-
-static int dlfb_parse_vendor_descriptor(struct dlfb_data *dlfb,
-					struct usb_interface *intf)
-{
-	char *desc;
-	char *buf;
-	char *desc_end;
-	int total_len;
-
-	buf = kzalloc(MAX_VENDOR_DESCRIPTOR_SIZE, GFP_KERNEL);
-	if (!buf)
-		return false;
-	desc = buf;
-
-	total_len = usb_get_descriptor(interface_to_usbdev(intf),
-					0x5f, /* vendor specific */
-					0, desc, MAX_VENDOR_DESCRIPTOR_SIZE);
-
-	/* if not found, look in configuration descriptor */
-	if (total_len < 0) {
-		if (0 == usb_get_extra_descriptor(intf->cur_altsetting,
-			0x5f, &desc))
-			total_len = (int) desc[0];
-	}
-
-	if (total_len > 5) {
-		dev_info(&intf->dev,
-			 "vendor descriptor length: %d data: %11ph\n",
-			 total_len, desc);
-
-		if ((desc[0] != total_len) || /* descriptor length */
-		    (desc[1] != 0x5f) ||   /* vendor descriptor type */
-		    (desc[2] != 0x01) ||   /* version (2 bytes) */
-		    (desc[3] != 0x00) ||
-		    (desc[4] != total_len - 2)) /* length after type */
-			goto unrecognized;
-
-		desc_end = desc + total_len;
-		desc += 5; /* the fixed header we've already parsed */
-
-		while (desc < desc_end) {
-			u8 length;
-			u16 key;
-
-			key = *desc++;
-			key |= (u16)*desc++ << 8;
-			length = *desc++;
-
-			switch (key) {
-			case 0x0200: { /* max_area */
-				u32 max_area = *desc++;
-				max_area |= (u32)*desc++ << 8;
-				max_area |= (u32)*desc++ << 16;
-				max_area |= (u32)*desc++ << 24;
-				dev_warn(&intf->dev,
-					 "DL chip limited to %d pixel modes\n",
-					 max_area);
-				dlfb->sku_pixel_limit = max_area;
-				break;
-			}
-			default:
-				break;
-			}
-			desc += length;
-		}
-	} else {
-		dev_info(&intf->dev, "vendor descriptor not available (%d)\n",
-			 total_len);
-	}
-
-	goto success;
-
-unrecognized:
-	/* allow udlfb to load for now even if firmware unrecognized */
-	dev_err(&intf->dev, "Unrecognized vendor firmware descriptor\n");
-
-success:
-	kfree(buf);
-	return true;
-}
-
-static int dlfb_usb_probe(struct usb_interface *intf,
-			  const struct usb_device_id *id)
-{
-	int i;
-	const struct device_attribute *attr;
-	struct dlfb_data *dlfb;
-	struct fb_info *info;
-	int retval = -ENOMEM;
-	struct usb_device *usbdev = interface_to_usbdev(intf);
-
-	/* usb initialization */
-	dlfb = kzalloc(sizeof(*dlfb), GFP_KERNEL);
-	if (!dlfb) {
-		dev_err(&intf->dev, "%s: failed to allocate dlfb\n", __func__);
-		return -ENOMEM;
-	}
-
-	INIT_LIST_HEAD(&dlfb->deferred_free);
-
-	dlfb->udev = usb_get_dev(usbdev);
-	usb_set_intfdata(intf, dlfb);
-
-	dev_dbg(&intf->dev, "console enable=%d\n", console);
-	dev_dbg(&intf->dev, "fb_defio enable=%d\n", fb_defio);
-	dev_dbg(&intf->dev, "shadow enable=%d\n", shadow);
-
-	dlfb->sku_pixel_limit = 2048 * 1152; /* default to maximum */
-
-	if (!dlfb_parse_vendor_descriptor(dlfb, intf)) {
-		dev_err(&intf->dev,
-			"firmware not recognized, incompatible device?\n");
-		goto error;
-	}
-
-	if (pixel_limit) {
-		dev_warn(&intf->dev,
-			 "DL chip limit of %d overridden to %d\n",
-			 dlfb->sku_pixel_limit, pixel_limit);
-		dlfb->sku_pixel_limit = pixel_limit;
-	}
-
-
-	/* allocates framebuffer driver structure, not framebuffer memory */
-	info = framebuffer_alloc(0, &dlfb->udev->dev);
-	if (!info)
-		goto error;
-
-	dlfb->info = info;
-	info->par = dlfb;
-	info->pseudo_palette = dlfb->pseudo_palette;
-	dlfb->ops = dlfb_ops;
-	info->fbops = &dlfb->ops;
-
-	mutex_init(&dlfb->render_mutex);
-	dlfb_init_damage(dlfb);
-	spin_lock_init(&dlfb->damage_lock);
-	INIT_WORK(&dlfb->damage_work, dlfb_damage_work);
-
-	INIT_LIST_HEAD(&info->modelist);
-
-	if (!dlfb_alloc_urb_list(dlfb, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
-		retval = -ENOMEM;
-		dev_err(&intf->dev, "unable to allocate urb list\n");
-		goto error;
-	}
-
-	/* We don't register a new USB class. Our client interface is dlfbev */
-
-	retval = fb_alloc_cmap(&info->cmap, 256, 0);
-	if (retval < 0) {
-		dev_err(info->device, "cmap allocation failed: %d\n", retval);
-		goto error;
-	}
-
-	retval = dlfb_setup_modes(dlfb, info, NULL, 0);
-	if (retval != 0) {
-		dev_err(info->device,
-			"unable to find common mode for display and adapter\n");
-		goto error;
-	}
-
-	/* ready to begin using device */
-
-	atomic_set(&dlfb->usb_active, 1);
-	dlfb_select_std_channel(dlfb);
-
-	dlfb_ops_check_var(&info->var, info);
-	retval = dlfb_ops_set_par(info);
-	if (retval)
-		goto error;
-
-	retval = register_framebuffer(info);
-	if (retval < 0) {
-		dev_err(info->device, "unable to register framebuffer: %d\n",
-			retval);
-		goto error;
-	}
-
-	for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++) {
-		attr = &fb_device_attrs[i];
-		retval = device_create_file(info->dev, attr);
-		if (retval)
-			dev_warn(info->device,
-				 "failed to create '%s' attribute: %d\n",
-				 attr->attr.name, retval);
-	}
-
-	retval = device_create_bin_file(info->dev, &edid_attr);
-	if (retval)
-		dev_warn(info->device, "failed to create '%s' attribute: %d\n",
-			 edid_attr.attr.name, retval);
-
-	dev_info(info->device,
-		 "%s is DisplayLink USB device (%dx%d, %dK framebuffer memory)\n",
-		 dev_name(info->dev), info->var.xres, info->var.yres,
-		 ((dlfb->backing_buffer) ?
-		 info->fix.smem_len * 2 : info->fix.smem_len) >> 10);
-	return 0;
-
-error:
-	if (dlfb->info) {
-		dlfb_ops_destroy(dlfb->info);
-	} else {
-		usb_put_dev(dlfb->udev);
-		kfree(dlfb);
-	}
-	return retval;
-}
-
-static void dlfb_usb_disconnect(struct usb_interface *intf)
-{
-	struct dlfb_data *dlfb;
-	struct fb_info *info;
-	int i;
-
-	dlfb = usb_get_intfdata(intf);
-	info = dlfb->info;
-
-	dev_dbg(&intf->dev, "USB disconnect starting\n");
-
-	/* we virtualize until all fb clients release. Then we free */
-	dlfb->virtualized = true;
-
-	/* When non-active we'll update virtual framebuffer, but no new urbs */
-	atomic_set(&dlfb->usb_active, 0);
-
-	/* this function will wait for all in-flight urbs to complete */
-	dlfb_free_urb_list(dlfb);
-
-	/* remove udlfb's sysfs interfaces */
-	for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
-		device_remove_file(info->dev, &fb_device_attrs[i]);
-	device_remove_bin_file(info->dev, &edid_attr);
-
-	unregister_framebuffer(info);
-}
-
-static struct usb_driver dlfb_driver = {
-	.name = "udlfb",
-	.probe = dlfb_usb_probe,
-	.disconnect = dlfb_usb_disconnect,
-	.id_table = id_table,
-};
-
-module_usb_driver(dlfb_driver);
-
-static void dlfb_urb_completion(struct urb *urb)
-{
-	struct urb_node *unode = urb->context;
-	struct dlfb_data *dlfb = unode->dlfb;
-	unsigned long flags;
-
-	switch (urb->status) {
-	case 0:
-		/* success */
-		break;
-	case -ECONNRESET:
-	case -ENOENT:
-	case -ESHUTDOWN:
-		/* sync/async unlink faults aren't errors */
-		break;
-	default:
-		dev_err(&dlfb->udev->dev,
-			"%s - nonzero write bulk status received: %d\n",
-			__func__, urb->status);
-		atomic_set(&dlfb->lost_pixels, 1);
-		break;
-	}
-
-	urb->transfer_buffer_length = dlfb->urbs.size; /* reset to actual */
-
-	spin_lock_irqsave(&dlfb->urbs.lock, flags);
-	list_add_tail(&unode->entry, &dlfb->urbs.list);
-	dlfb->urbs.available++;
-	spin_unlock_irqrestore(&dlfb->urbs.lock, flags);
-
-	up(&dlfb->urbs.limit_sem);
-}
-
-static void dlfb_free_urb_list(struct dlfb_data *dlfb)
-{
-	int count = dlfb->urbs.count;
-	struct list_head *node;
-	struct urb_node *unode;
-	struct urb *urb;
-
-	/* keep waiting and freeing, until we've got 'em all */
-	while (count--) {
-		down(&dlfb->urbs.limit_sem);
-
-		spin_lock_irq(&dlfb->urbs.lock);
-
-		node = dlfb->urbs.list.next; /* have reserved one with sem */
-		list_del_init(node);
-
-		spin_unlock_irq(&dlfb->urbs.lock);
-
-		unode = list_entry(node, struct urb_node, entry);
-		urb = unode->urb;
-
-		/* Free each separately allocated piece */
-		usb_free_coherent(urb->dev, dlfb->urbs.size,
-				  urb->transfer_buffer, urb->transfer_dma);
-		usb_free_urb(urb);
-		kfree(node);
-	}
-
-	dlfb->urbs.count = 0;
-}
-
-static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size)
-{
-	struct urb *urb;
-	struct urb_node *unode;
-	char *buf;
-	size_t wanted_size = count * size;
-
-	spin_lock_init(&dlfb->urbs.lock);
-
-retry:
-	dlfb->urbs.size = size;
-	INIT_LIST_HEAD(&dlfb->urbs.list);
-
-	sema_init(&dlfb->urbs.limit_sem, 0);
-	dlfb->urbs.count = 0;
-	dlfb->urbs.available = 0;
-
-	while (dlfb->urbs.count * size < wanted_size) {
-		unode = kzalloc(sizeof(*unode), GFP_KERNEL);
-		if (!unode)
-			break;
-		unode->dlfb = dlfb;
-
-		urb = usb_alloc_urb(0, GFP_KERNEL);
-		if (!urb) {
-			kfree(unode);
-			break;
-		}
-		unode->urb = urb;
-
-		buf = usb_alloc_coherent(dlfb->udev, size, GFP_KERNEL,
-					 &urb->transfer_dma);
-		if (!buf) {
-			kfree(unode);
-			usb_free_urb(urb);
-			if (size > PAGE_SIZE) {
-				size /= 2;
-				dlfb_free_urb_list(dlfb);
-				goto retry;
-			}
-			break;
-		}
-
-		/* urb->transfer_buffer_length set to actual before submit */
-		usb_fill_bulk_urb(urb, dlfb->udev, usb_sndbulkpipe(dlfb->udev, 1),
-			buf, size, dlfb_urb_completion, unode);
-		urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
-
-		list_add_tail(&unode->entry, &dlfb->urbs.list);
-
-		up(&dlfb->urbs.limit_sem);
-		dlfb->urbs.count++;
-		dlfb->urbs.available++;
-	}
-
-	return dlfb->urbs.count;
-}
-
-static struct urb *dlfb_get_urb(struct dlfb_data *dlfb)
-{
-	int ret;
-	struct list_head *entry;
-	struct urb_node *unode;
-
-	/* Wait for an in-flight buffer to complete and get re-queued */
-	ret = down_timeout(&dlfb->urbs.limit_sem, GET_URB_TIMEOUT);
-	if (ret) {
-		atomic_set(&dlfb->lost_pixels, 1);
-		dev_warn(&dlfb->udev->dev,
-			 "wait for urb interrupted: %d available: %d\n",
-			 ret, dlfb->urbs.available);
-		return NULL;
-	}
-
-	spin_lock_irq(&dlfb->urbs.lock);
-
-	BUG_ON(list_empty(&dlfb->urbs.list)); /* reserved one with limit_sem */
-	entry = dlfb->urbs.list.next;
-	list_del_init(entry);
-	dlfb->urbs.available--;
-
-	spin_unlock_irq(&dlfb->urbs.lock);
-
-	unode = list_entry(entry, struct urb_node, entry);
-	return unode->urb;
-}
-
-static int dlfb_submit_urb(struct dlfb_data *dlfb, struct urb *urb, size_t len)
-{
-	int ret;
-
-	BUG_ON(len > dlfb->urbs.size);
-
-	urb->transfer_buffer_length = len; /* set to actual payload len */
-	ret = usb_submit_urb(urb, GFP_KERNEL);
-	if (ret) {
-		dlfb_urb_completion(urb); /* because no one else will */
-		atomic_set(&dlfb->lost_pixels, 1);
-		dev_err(&dlfb->udev->dev, "submit urb error: %d\n", ret);
-	}
-	return ret;
-}
-
-module_param(console, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
-MODULE_PARM_DESC(console, "Allow fbcon to open framebuffer");
-
-module_param(fb_defio, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
-MODULE_PARM_DESC(fb_defio, "Page fault detection of mmap writes");
-
-module_param(shadow, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
-MODULE_PARM_DESC(shadow, "Shadow vid mem. Disable to save mem but lose perf");
-
-module_param(pixel_limit, int, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
-MODULE_PARM_DESC(pixel_limit, "Force limit on max mode (in x*y pixels)");
-
-MODULE_AUTHOR("Roberto De Ioris <roberto@unbit.it>, "
-	      "Jaya Kumar <jayakumar.lkml@gmail.com>, "
-	      "Bernie Thompson <bernie@plugable.com>");
-MODULE_DESCRIPTION("DisplayLink kernel framebuffer driver");
-MODULE_LICENSE("GPL");
-
-- 
2.29.2


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-11-30 12:52 [PATCH] fbdev: Remove udlfb driver Thomas Zimmermann
@ 2020-11-30 14:31 ` Mikulas Patocka
  2020-11-30 15:41   ` Daniel Vetter
  2020-12-01  8:02   ` Thomas Zimmermann
  0 siblings, 2 replies; 15+ messages in thread
From: Mikulas Patocka @ 2020-11-30 14:31 UTC (permalink / raw)
  To: Thomas Zimmermann
  Cc: daniel.vetter, sam, geert+renesas, bernie, corbet, dri-devel,
	linux-fbdev, linux-doc



On Mon, 30 Nov 2020, Thomas Zimmermann wrote:

> Udlfb has been superseded by DRM's udl. The DRM driver is better by
> any means and actively maintained. Remove udlfb.

Hi

I am using udlfb and it's definitely better than the DRM driver. The DRM 
driver will crash the kernel if you unplug the device while Xorg is 
running. The framebuffer driver doesn't crash in this case. (I have a cat 
and the cat sometimes unplugs cables and I don't want to reboot the system 
because of it :-)

The framebuffer driver is faster, it keeps back buffer and updates only 
data that differ between the front and back buffer. The DRM driver doesn't 
have such optimization, it will update everything in a given rectangle - 
this increases USB traffic and makes video playback more jerky.

The framebuffer driver supports programs running full-screen directly on 
the framebuffer console, such as web browser "links -g", image viewer 
"fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl", 
movie player "mplayer -vo fbdev". The DRM driver doesn't run them.

If you seach for someone to maintain the framebuffer driver, I can do it.

Mikulas


> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  CREDITS                      |    5 +
>  Documentation/fb/index.rst   |    1 -
>  Documentation/fb/udlfb.rst   |  162 ---
>  MAINTAINERS                  |    9 -
>  drivers/video/fbdev/Kconfig  |   17 +-
>  drivers/video/fbdev/Makefile |    1 -
>  drivers/video/fbdev/udlfb.c  | 1994 ----------------------------------
>  7 files changed, 6 insertions(+), 2183 deletions(-)
>  delete mode 100644 Documentation/fb/udlfb.rst
>  delete mode 100644 drivers/video/fbdev/udlfb.c


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-11-30 14:31 ` Mikulas Patocka
@ 2020-11-30 15:41   ` Daniel Vetter
  2020-11-30 18:39     ` Mikulas Patocka
  2020-12-01  8:02   ` Thomas Zimmermann
  1 sibling, 1 reply; 15+ messages in thread
From: Daniel Vetter @ 2020-11-30 15:41 UTC (permalink / raw)
  To: Mikulas Patocka
  Cc: Thomas Zimmermann, linux-fbdev, geert+renesas, corbet,
	daniel.vetter, linux-doc, bernie, dri-devel, sam

On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote:
> 
> 
> On Mon, 30 Nov 2020, Thomas Zimmermann wrote:
> 
> > Udlfb has been superseded by DRM's udl. The DRM driver is better by
> > any means and actively maintained. Remove udlfb.
> 
> Hi
> 
> I am using udlfb and it's definitely better than the DRM driver. The DRM 
> driver will crash the kernel if you unplug the device while Xorg is 
> running. The framebuffer driver doesn't crash in this case. (I have a cat 
> and the cat sometimes unplugs cables and I don't want to reboot the system 
> because of it :-)

This should be a lot better in recent kernels, there's been tons of fixes
for drm hotunplug. Might be there's still bugs in the drm/udl driver.

> The framebuffer driver is faster, it keeps back buffer and updates only 
> data that differ between the front and back buffer. The DRM driver doesn't 
> have such optimization, it will update everything in a given rectangle - 
> this increases USB traffic and makes video playback more jerky.
> 
> The framebuffer driver supports programs running full-screen directly on 
> the framebuffer console, such as web browser "links -g", image viewer 
> "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl", 
> movie player "mplayer -vo fbdev". The DRM driver doesn't run them.

Hm this should in general work on drm drivers. Without that it's clear the
switch-over isn't really ready yet.

> If you seach for someone to maintain the framebuffer driver, I can do it.

We're looking for people to port the missing features over to the drm
drivers. The problem is that fbdev is full of security bugs, and we're
fixing them by removing the features. So that's why there's some push to
sunset at much as possible.
-Daniel

> 
> Mikulas
> 
> 
> > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> > ---
> >  CREDITS                      |    5 +
> >  Documentation/fb/index.rst   |    1 -
> >  Documentation/fb/udlfb.rst   |  162 ---
> >  MAINTAINERS                  |    9 -
> >  drivers/video/fbdev/Kconfig  |   17 +-
> >  drivers/video/fbdev/Makefile |    1 -
> >  drivers/video/fbdev/udlfb.c  | 1994 ----------------------------------
> >  7 files changed, 6 insertions(+), 2183 deletions(-)
> >  delete mode 100644 Documentation/fb/udlfb.rst
> >  delete mode 100644 drivers/video/fbdev/udlfb.c
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-11-30 15:41   ` Daniel Vetter
@ 2020-11-30 18:39     ` Mikulas Patocka
  2020-11-30 21:06       ` Daniel Vetter
  2020-12-01  8:07       ` Thomas Zimmermann
  0 siblings, 2 replies; 15+ messages in thread
From: Mikulas Patocka @ 2020-11-30 18:39 UTC (permalink / raw)
  To: Daniel Vetter
  Cc: Thomas Zimmermann, linux-fbdev, geert+renesas, corbet,
	daniel.vetter, linux-doc, bernie, dri-devel, sam



On Mon, 30 Nov 2020, Daniel Vetter wrote:

> On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote:
> > 
> > The framebuffer driver supports programs running full-screen directly on 
> > the framebuffer console, such as web browser "links -g", image viewer 
> > "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl", 
> > movie player "mplayer -vo fbdev". The DRM driver doesn't run them.
> 
> Hm this should in general work on drm drivers. Without that it's clear the
> switch-over isn't really ready yet.

I fixed it with this patch two years ago: 
https://lists.freedesktop.org/archives/dri-devel/2018-June/179023.html

But the patch never went through and the fb_defio feature was removed in 
the kernel 5.6 (commit d0c4fc5a4814e431c15272935c8dc973c18073aa).


Without fb_defio, the only other possibility how to update the screen is 
the ioctl DRM_IOCTL_MODE_DIRTYFB. But this ioctl requires master mode, so 
user programs like "links -g" can't issue it.

Mikulas


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-11-30 18:39     ` Mikulas Patocka
@ 2020-11-30 21:06       ` Daniel Vetter
  2020-12-01 11:26         ` Mikulas Patocka
  2020-12-01  8:07       ` Thomas Zimmermann
  1 sibling, 1 reply; 15+ messages in thread
From: Daniel Vetter @ 2020-11-30 21:06 UTC (permalink / raw)
  To: Mikulas Patocka
  Cc: Daniel Vetter, Thomas Zimmermann, linux-fbdev, geert+renesas,
	corbet, daniel.vetter, linux-doc, bernie, dri-devel, sam

On Mon, Nov 30, 2020 at 01:39:17PM -0500, Mikulas Patocka wrote:
> 
> 
> On Mon, 30 Nov 2020, Daniel Vetter wrote:
> 
> > On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote:
> > > 
> > > The framebuffer driver supports programs running full-screen directly on 
> > > the framebuffer console, such as web browser "links -g", image viewer 
> > > "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl", 
> > > movie player "mplayer -vo fbdev". The DRM driver doesn't run them.
> > 
> > Hm this should in general work on drm drivers. Without that it's clear the
> > switch-over isn't really ready yet.
> 
> I fixed it with this patch two years ago: 
> https://lists.freedesktop.org/archives/dri-devel/2018-June/179023.html
> 
> But the patch never went through and the fb_defio feature was removed in 
> the kernel 5.6 (commit d0c4fc5a4814e431c15272935c8dc973c18073aa).

The generic fbdev emulation still has a defio implementation. We could try
to make it more efficient maybe, but it should be all there. The module
option disappeared since you now should always get it by default.

> Without fb_defio, the only other possibility how to update the screen is 
> the ioctl DRM_IOCTL_MODE_DIRTYFB. But this ioctl requires master mode, so 
> user programs like "links -g" can't issue it.

Now I'm confused, I thought you wanted to use fbdev /dev/fb* nodes? Those
should support defio. And if you want your applications to use drm
modesetting natively, they have to be drm master anyway. You can't use the
DIRTYFB ioctl to upload fbdev contents. So I'm a bit confused.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-11-30 14:31 ` Mikulas Patocka
  2020-11-30 15:41   ` Daniel Vetter
@ 2020-12-01  8:02   ` Thomas Zimmermann
  2020-12-01 10:44     ` Mikulas Patocka
  1 sibling, 1 reply; 15+ messages in thread
From: Thomas Zimmermann @ 2020-12-01  8:02 UTC (permalink / raw)
  To: Mikulas Patocka
  Cc: daniel.vetter, sam, geert+renesas, bernie, corbet, dri-devel,
	linux-fbdev, linux-doc


[-- Attachment #1.1: Type: text/plain, Size: 2547 bytes --]

Hi

Am 30.11.20 um 15:31 schrieb Mikulas Patocka:
> 
> 
> On Mon, 30 Nov 2020, Thomas Zimmermann wrote:
> 
>> Udlfb has been superseded by DRM's udl. The DRM driver is better by
>> any means and actively maintained. Remove udlfb.
> 
> Hi
> 
> I am using udlfb and it's definitely better than the DRM driver. The DRM
> driver will crash the kernel if you unplug the device while Xorg is
> running. The framebuffer driver doesn't crash in this case. (I have a cat
> and the cat sometimes unplugs cables and I don't want to reboot the system
> because of it :-)

What's the exact STR here? Just open the /dev/fb* and pull the cable.

Do I need a cat? :)

> The framebuffer driver is faster, it keeps back buffer and updates only
> data that differ between the front and back buffer. The DRM driver doesn't
> have such optimization, it will update everything in a given rectangle -
> this increases USB traffic and makes video playback more jerky.

That's not quite true, but not false either. I think we could optimize 
what we have.

> 
> The framebuffer driver supports programs running full-screen directly on
> the framebuffer console, such as web browser "links -g", image viewer
> "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl",
> movie player "mplayer -vo fbdev". The DRM driver doesn't run them.

I would expect that most programs have an SDL2 backend. (?) IIRC SDL2 
has support for DRI interfaces.

> 
> If you seach for someone to maintain the framebuffer driver, I can do it.

I'm looking for reasons why udlfb is still around. What I got from this 
thread is the possible crash and a lack of DRM's fbdev performance. 
Thanks for the feedback.

Best regards
Thomas

> 
> Mikulas
> 
> 
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> ---
>>   CREDITS                      |    5 +
>>   Documentation/fb/index.rst   |    1 -
>>   Documentation/fb/udlfb.rst   |  162 ---
>>   MAINTAINERS                  |    9 -
>>   drivers/video/fbdev/Kconfig  |   17 +-
>>   drivers/video/fbdev/Makefile |    1 -
>>   drivers/video/fbdev/udlfb.c  | 1994 ----------------------------------
>>   7 files changed, 6 insertions(+), 2183 deletions(-)
>>   delete mode 100644 Documentation/fb/udlfb.rst
>>   delete mode 100644 drivers/video/fbdev/udlfb.c
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-11-30 18:39     ` Mikulas Patocka
  2020-11-30 21:06       ` Daniel Vetter
@ 2020-12-01  8:07       ` Thomas Zimmermann
  2020-12-01 11:20         ` Mikulas Patocka
  1 sibling, 1 reply; 15+ messages in thread
From: Thomas Zimmermann @ 2020-12-01  8:07 UTC (permalink / raw)
  To: Mikulas Patocka, Daniel Vetter
  Cc: linux-fbdev, geert+renesas, corbet, daniel.vetter, linux-doc,
	bernie, dri-devel, sam


[-- Attachment #1.1: Type: text/plain, Size: 1549 bytes --]

Hi

Am 30.11.20 um 19:39 schrieb Mikulas Patocka:
> 
> 
> On Mon, 30 Nov 2020, Daniel Vetter wrote:
> 
>> On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote:
>>>
>>> The framebuffer driver supports programs running full-screen directly on
>>> the framebuffer console, such as web browser "links -g", image viewer
>>> "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl",
>>> movie player "mplayer -vo fbdev". The DRM driver doesn't run them.
>>
>> Hm this should in general work on drm drivers. Without that it's clear the
>> switch-over isn't really ready yet.
> 
> I fixed it with this patch two years ago:
> https://lists.freedesktop.org/archives/dri-devel/2018-June/179023.html
> 
> But the patch never went through and the fb_defio feature was removed in
> the kernel 5.6 (commit d0c4fc5a4814e431c15272935c8dc973c18073aa).
> 
> 
> Without fb_defio, the only other possibility how to update the screen is
> the ioctl DRM_IOCTL_MODE_DIRTYFB. But this ioctl requires master mode, so
> user programs like "links -g" can't issue it.

That's confusing. DIRTYFB is only for DRM.

And why can links not run as DRM master mode? If it renders to the 
terminal, it should act like a composer. In that case it almost 
certainly wants master status.

Best regards
Thomas

> 
> Mikulas
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-12-01  8:02   ` Thomas Zimmermann
@ 2020-12-01 10:44     ` Mikulas Patocka
  2020-12-01 20:09       ` Mikulas Patocka
  0 siblings, 1 reply; 15+ messages in thread
From: Mikulas Patocka @ 2020-12-01 10:44 UTC (permalink / raw)
  To: Thomas Zimmermann
  Cc: daniel.vetter, sam, geert+renesas, bernie, corbet, dri-devel,
	linux-fbdev, linux-doc



On Tue, 1 Dec 2020, Thomas Zimmermann wrote:

> Hi
> 
> Am 30.11.20 um 15:31 schrieb Mikulas Patocka:
> > 
> > 
> > On Mon, 30 Nov 2020, Thomas Zimmermann wrote:
> > 
> > > Udlfb has been superseded by DRM's udl. The DRM driver is better by
> > > any means and actively maintained. Remove udlfb.
> > 
> > Hi
> > 
> > I am using udlfb and it's definitely better than the DRM driver. The DRM
> > driver will crash the kernel if you unplug the device while Xorg is
> > running. The framebuffer driver doesn't crash in this case. (I have a cat
> > and the cat sometimes unplugs cables and I don't want to reboot the system
> > because of it :-)
> 
> What's the exact STR here? Just open the /dev/fb* and pull the cable.
> 
> Do I need a cat? :)

When I run links -g on the DRM driver, it works at first, but after some 
unplug/plug I got this:

[  282.174963] general protection fault, probably for non-canonical address 0xdead0000000000f8: 0000 [#1] PREEMPT SMP
[  282.177439] CPU: 9 PID: 3377 Comm: links Not tainted 5.10.0-rc6 #1
[  282.178843] Hardware name: empty empty/S3992-E, BIOS 'V1.06   ' 06/09/2009
[  282.180325] RIP: 0010:fb_deferred_io_mkwrite+0x7c/0x100 [fb]
[  282.181865] Code: ff 83 e2 01 48 0f 44 c3 f0 48 0f ba 28 00 0f 82 83 00 00 00 49 8b 45 28 49 39 c4 48 8d 50 f8 74 5d 48 39 d3 74 1c 48 8b 4b 20 <48> 39 4a 20 77 4e 48 8b 42 08 4c 39 e0 48 8d 50 f8 74 41 48 39 d3
[  282.185341] RSP: 0000:ffff888348293de8 EFLAGS: 00010216
[  282.187166] RAX: dead000000000100 RBX: ffffea0004182980 RCX: 0000000000000000
[  282.189071] RDX: dead0000000000f8 RSI: 0000000000000801 RDI: ffffffffa045c048
[  282.191021] RBP: ffff888106af1c00 R08: 000000005fc6128b R09: 000000003626d41e
[  282.193006] R10: 0000000000000008 R11: ffff88a04fffc000 R12: ffffffffa045c068
[  282.195015] R13: ffffffffa045c040 R14: ffffffffa045c048 R15: fff000003fffffff
[  282.197077] FS:  00007fa64cbf4a00(0000) GS:ffff88a00fcc0000(0000) knlGS:0000000000000000
[  282.199293] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  282.201484] CR2: 00007fa63f272008 CR3: 000000105b2e0000 CR4: 00000000000006e0
[  282.203728] Call Trace:
[  282.205927]  do_page_mkwrite+0x56/0xc0
[  282.208125]  ? __do_fault+0x2d/0xe0
[  282.210257]  handle_mm_fault+0xafc/0x15e0
[  282.212350]  exc_page_fault+0x1ac/0x4a0
[  282.214408]  ? asm_exc_page_fault+0x8/0x30
[  282.216473]  asm_exc_page_fault+0x1e/0x30
[  282.218462] RIP: 0033:0x7fa64641f3a8
[  282.220469] Code: c3 48 81 fa 00 08 00 00 77 a8 48 83 fa 40 77 16 f3 0f 7f 07 f3 0f 7f 47 10 f3 0f 7f 44 17 f0 f3 0f 7f 44 17 e0 c3 48 8d 4f 40 <f3> 0f 7f 07 48 83 e1 c0 f3 0f 7f 44 17 f0 f3 0f 7f 47 10 f3 0f 7f
[  282.224730] RSP: 002b:00007ffe6da66ba8 EFLAGS: 00010206
[  282.226881] RAX: 00007fa63f272000 RBX: 00007fa64cbf4990 RCX: 00007fa63f272040
[  282.229094] RDX: 00000000003f4800 RSI: 0000000000000000 RDI: 00007fa63f272000
[  282.231339] RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffffffffffff
[  282.233614] R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000f00
[  282.235927] R13: 00000000003f4800 R14: 00000000003f4800 R15: 0000000000000005
[  282.238262] Modules linked in: mousedev hid_generic usbhid hid iptable_mangle ipt_REJECT nf_reject_ipv4 tun xt_MASQUERADE iptable_nat xt_tcpudp iscsi_target_mod target_core_pscsi target_core_file ip6table_filter ip6_tables iptable_filter ip_tables x_tables af_packet target_core_mod cpufreq_powersave cpufreq_ondemand cpufreq_userspace configfs
cpufreq_conservative autofs4 binfmt_misc bridge stp llc snd_usb_audio snd_hwdep snd_usbmidi_lib snd_rawmidi snd_pcm snd_timer snd soundcore dmi_sysfs nf_nat_ftp nf_conntrack_ftp nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 lm85 hwmon_vid udl drm_kms_helper cfbfillrect syscopyarea cfbimgblt sysfillrect sysimgblt fb_sys_fops cfbcopyarea fb font fbdev drm drm_panel_orientation_quirks backlight ipv6 ohci_pci amd64_edac_mod edac_mce_amd kvm_amd kvm irqbypass tg3 pcspkr ptp pps_core ehci_pci ohci_hcd ehci_hcd libphy usbcore k10temp hwmon e100 usb_common mii i2c_piix4 pata_serverworks rtc_cmos floppy acpi_cpufreq button processor spadfs evdev
[  282.257235] ---[ end trace d7968a41c1fbf717 ]---
[  282.267115] RIP: 0010:fb_deferred_io_mkwrite+0x7c/0x100 [fb]
[  282.270350] Code: ff 83 e2 01 48 0f 44 c3 f0 48 0f ba 28 00 0f 82 83 00 00 00 49 8b 45 28 49 39 c4 48 8d 50 f8 74 5d 48 39 d3 74 1c 48 8b 4b 20 <48> 39 4a 20 77 4e 48 8b 42 08 4c 39 e0 48 8d 50 f8 74 41 48 39 d3
[  282.276893] RSP: 0000:ffff888348293de8 EFLAGS: 00010216
[  282.280202] RAX: dead000000000100 RBX: ffffea0004182980 RCX: 0000000000000000
[  282.283564] RDX: dead0000000000f8 RSI: 0000000000000801 RDI: ffffffffa045c048
[  282.286965] RBP: ffff888106af1c00 R08: 000000005fc6128b R09: 000000003626d41e
[  282.290628] R10: 0000000000000008 R11: ffff88a04fffc000 R12: ffffffffa045c068
[  282.294039] R13: ffffffffa045c040 R14: ffffffffa045c048 R15: fff000003fffffff
[  282.297430] FS:  00007fa64cbf4a00(0000) GS:ffff88900fd00000(0000) knlGS:0000000000000000


When I try to run Xorg (from Debian 9) with the kernel 5.10-rc6, it 
doesn't work at all, I get this crash:

[   451.002] (EE) FBDEV(0): FBIOPUTCMAP: Device or resource busy
[   451.002] (==) FBDEV(0): DPMS enabled
[   451.002] (--) RandR disabled
[   451.008] (II) SELinux: Disabled on system
[   451.008] (II) AIGLX: Screen 0 is not DRI2 capable
[   451.008] (EE) AIGLX: reverting to software rendering
[   451.011] (II) IGLX: enabled GLX_MESA_copy_sub_buffer
[   451.011] (II) IGLX: Loaded and initialized swrast
[   451.011] (II) GLX: Initialized DRISWRAST GL provider for screen 0
[   451.012] (II) modeset(G0): Damage tracking initialized
[   451.012] (EE)
[   451.012] (EE) Backtrace:
[   451.013] (EE) 0: /usr/lib/xorg/Xorg (xorg_backtrace+0x4a) [0x5611eb3b973a]
[   451.013] (EE) 1: /usr/lib/xorg/Xorg (0x5611eb200000+0x1bd4c9) [0x5611eb3bd4c9]
[   451.013] (EE) 2: /lib/x86_64-linux-gnu/libpthread.so.0 (0x7fd7dbb16000+0x110e0) [0x7fd7dbb270e0]
[   451.013] (EE) 3: /usr/lib/xorg/Xorg (RRSetChanged+0x92) [0x5611eb3175f2]
[   451.013] (EE) 4: /usr/lib/xorg/Xorg (RRScreenSetSizeRange+0x54) [0x5611eb31c1b4]
[   451.013] (EE) 5: /usr/lib/xorg/Xorg (xf86RandR12CreateScreenResources+0x310) [0x5611eb2d59d0]
[   451.013] (EE) 6: /usr/lib/xorg/Xorg (0x5611eb200000+0xc8b60) [0x5611eb2c8b60]
[   451.013] (EE) 7: /usr/lib/xorg/Xorg (0x5611eb200000+0x590c1) [0x5611eb2590c1]
[   451.013] (EE) 8: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf1) [0x7fd7db7972e1]
[   451.013] (EE) 9: /usr/lib/xorg/Xorg (_start+0x2a) [0x5611eb242f0a]
[   451.013] (EE)
[   451.013] (EE) Segmentation fault at address 0xb8
[   451.013] (EE)
Fatal server error:
[   451.013] (EE) Caught signal 11 (Segmentation fault). Server aborting
[   451.013] (EE)
[   451.013] (EE)
Please consult the The X.Org Foundation support
         at http://wiki.x.org
 for help.
[   451.013] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[   451.013] (EE)
[   451.063] (EE) Server terminated with error (1). Closing log file.


Mikulas


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-12-01  8:07       ` Thomas Zimmermann
@ 2020-12-01 11:20         ` Mikulas Patocka
  2020-12-02  7:55           ` Thomas Zimmermann
  0 siblings, 1 reply; 15+ messages in thread
From: Mikulas Patocka @ 2020-12-01 11:20 UTC (permalink / raw)
  To: Thomas Zimmermann
  Cc: Daniel Vetter, linux-fbdev, geert+renesas, corbet, daniel.vetter,
	linux-doc, bernie, dri-devel, sam



On Tue, 1 Dec 2020, Thomas Zimmermann wrote:

> Hi
> 
> Am 30.11.20 um 19:39 schrieb Mikulas Patocka:
> > 
> > 
> > On Mon, 30 Nov 2020, Daniel Vetter wrote:
> > 
> > > On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote:
> > > > 
> > > > The framebuffer driver supports programs running full-screen directly on
> > > > the framebuffer console, such as web browser "links -g", image viewer
> > > > "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl",
> > > > movie player "mplayer -vo fbdev". The DRM driver doesn't run them.
> > > 
> > > Hm this should in general work on drm drivers. Without that it's clear the
> > > switch-over isn't really ready yet.
> > 
> > I fixed it with this patch two years ago:
> > https://lists.freedesktop.org/archives/dri-devel/2018-June/179023.html
> > 
> > But the patch never went through and the fb_defio feature was removed in
> > the kernel 5.6 (commit d0c4fc5a4814e431c15272935c8dc973c18073aa).
> > 
> > 
> > Without fb_defio, the only other possibility how to update the screen is
> > the ioctl DRM_IOCTL_MODE_DIRTYFB. But this ioctl requires master mode, so
> > user programs like "links -g" can't issue it.
> 
> That's confusing. DIRTYFB is only for DRM.

Yes, you're right.

> And why can links not run as DRM master mode? If it renders to the terminal,
> it should act like a composer. In that case it almost certainly wants master
> status.
> 
> Best regards
> Thomas

How can a userspace program acquire master mode without being suid?

Is there some "Hello World!" program that shows how to use DRM? I'm not an 
expert in DRM, but if there were some tutorial+documentation, I could 
consider porting "links" to it.

Mikulas


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-11-30 21:06       ` Daniel Vetter
@ 2020-12-01 11:26         ` Mikulas Patocka
  0 siblings, 0 replies; 15+ messages in thread
From: Mikulas Patocka @ 2020-12-01 11:26 UTC (permalink / raw)
  To: Daniel Vetter
  Cc: Thomas Zimmermann, linux-fbdev, geert+renesas, corbet,
	daniel.vetter, linux-doc, bernie, dri-devel, sam



On Mon, 30 Nov 2020, Daniel Vetter wrote:

> On Mon, Nov 30, 2020 at 01:39:17PM -0500, Mikulas Patocka wrote:
> > 
> > 
> > On Mon, 30 Nov 2020, Daniel Vetter wrote:
> > 
> > > On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote:
> > > > 
> > > > The framebuffer driver supports programs running full-screen directly on 
> > > > the framebuffer console, such as web browser "links -g", image viewer 
> > > > "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl", 
> > > > movie player "mplayer -vo fbdev". The DRM driver doesn't run them.
> > > 
> > > Hm this should in general work on drm drivers. Without that it's clear the
> > > switch-over isn't really ready yet.
> > 
> > I fixed it with this patch two years ago: 
> > https://lists.freedesktop.org/archives/dri-devel/2018-June/179023.html
> > 
> > But the patch never went through and the fb_defio feature was removed in 
> > the kernel 5.6 (commit d0c4fc5a4814e431c15272935c8dc973c18073aa).
> 
> The generic fbdev emulation still has a defio implementation. We could try
> to make it more efficient maybe, but it should be all there. The module
> option disappeared since you now should always get it by default.

Yes, it's there. I've tried to run links on the current DRM UDL driver and 
it displays correctly - except, that the page list gets sometimes 
corrupted and a crash happens.

> > Without fb_defio, the only other possibility how to update the screen is 
> > the ioctl DRM_IOCTL_MODE_DIRTYFB. But this ioctl requires master mode, so 
> > user programs like "links -g" can't issue it.
> 
> Now I'm confused, I thought you wanted to use fbdev /dev/fb* nodes? Those
> should support defio. And if you want your applications to use drm
> modesetting natively, they have to be drm master anyway. You can't use the
> DIRTYFB ioctl to upload fbdev contents. So I'm a bit confused.
> -Daniel

Yes. I was confused about it too. You can't use DRM ioctls on /dev/fb.

Mikulas


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-12-01 10:44     ` Mikulas Patocka
@ 2020-12-01 20:09       ` Mikulas Patocka
  0 siblings, 0 replies; 15+ messages in thread
From: Mikulas Patocka @ 2020-12-01 20:09 UTC (permalink / raw)
  To: Thomas Zimmermann
  Cc: daniel.vetter, sam, geert+renesas, bernie, corbet, dri-devel,
	linux-fbdev, linux-doc



On Tue, 1 Dec 2020, Mikulas Patocka wrote:

> When I try to run Xorg (from Debian 9) with the kernel 5.10-rc6, it 
> doesn't work at all, I get this crash:

I tried to rux Xorg on another machine (with up-to-date Debian ports) and 
it didn't crash on unplug.

Mikulas


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-12-01 11:20         ` Mikulas Patocka
@ 2020-12-02  7:55           ` Thomas Zimmermann
  2020-12-02  8:01             ` Thomas Zimmermann
                               ` (2 more replies)
  0 siblings, 3 replies; 15+ messages in thread
From: Thomas Zimmermann @ 2020-12-02  7:55 UTC (permalink / raw)
  To: Mikulas Patocka
  Cc: Daniel Vetter, linux-fbdev, geert+renesas, corbet, daniel.vetter,
	linux-doc, bernie, dri-devel, sam


[-- Attachment #1.1: Type: text/plain, Size: 2352 bytes --]

Hi

Am 01.12.20 um 12:20 schrieb Mikulas Patocka:
> 
> 
> On Tue, 1 Dec 2020, Thomas Zimmermann wrote:
> 
>> Hi
>>
>> Am 30.11.20 um 19:39 schrieb Mikulas Patocka:
>>>
>>>
>>> On Mon, 30 Nov 2020, Daniel Vetter wrote:
>>>
>>>> On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote:
>>>>>
>>>>> The framebuffer driver supports programs running full-screen directly on
>>>>> the framebuffer console, such as web browser "links -g", image viewer
>>>>> "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl",
>>>>> movie player "mplayer -vo fbdev". The DRM driver doesn't run them.
>>>>
>>>> Hm this should in general work on drm drivers. Without that it's clear the
>>>> switch-over isn't really ready yet.
>>>
>>> I fixed it with this patch two years ago:
>>> https://lists.freedesktop.org/archives/dri-devel/2018-June/179023.html
>>>
>>> But the patch never went through and the fb_defio feature was removed in
>>> the kernel 5.6 (commit d0c4fc5a4814e431c15272935c8dc973c18073aa).
>>>
>>>
>>> Without fb_defio, the only other possibility how to update the screen is
>>> the ioctl DRM_IOCTL_MODE_DIRTYFB. But this ioctl requires master mode, so
>>> user programs like "links -g" can't issue it.
>>
>> That's confusing. DIRTYFB is only for DRM.
> 
> Yes, you're right.
> 
>> And why can links not run as DRM master mode? If it renders to the terminal,
>> it should act like a composer. In that case it almost certainly wants master
>> status.
>>
>> Best regards
>> Thomas
> 
> How can a userspace program acquire master mode without being suid?

For my understanding, there's no easy solution to that. :/

I guess we (DRM devs) have to treat fbdev as the solution for use cases 
such as ours.

For the unplug issue, I'll try to reproduce and fix it.

For the performance problems, we might be able to squeeze a few more 
cycles out of it.

Best regards
Thomas

> 
> Is there some "Hello World!" program that shows how to use DRM? I'm not an
> expert in DRM, but if there were some tutorial+documentation, I could
> consider porting "links" to it.
> 
> Mikulas
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-12-02  7:55           ` Thomas Zimmermann
@ 2020-12-02  8:01             ` Thomas Zimmermann
  2020-12-02  8:29             ` Pekka Paalanen
  2020-12-02 17:52             ` Daniel Vetter
  2 siblings, 0 replies; 15+ messages in thread
From: Thomas Zimmermann @ 2020-12-02  8:01 UTC (permalink / raw)
  To: Mikulas Patocka
  Cc: Daniel Vetter, linux-fbdev, geert+renesas, corbet, daniel.vetter,
	linux-doc, bernie, dri-devel, sam


[-- Attachment #1.1: Type: text/plain, Size: 2558 bytes --]



Am 02.12.20 um 08:55 schrieb Thomas Zimmermann:
> Hi
> 
> Am 01.12.20 um 12:20 schrieb Mikulas Patocka:
>>
>>
>> On Tue, 1 Dec 2020, Thomas Zimmermann wrote:
>>
>>> Hi
>>>
>>> Am 30.11.20 um 19:39 schrieb Mikulas Patocka:
>>>>
>>>>
>>>> On Mon, 30 Nov 2020, Daniel Vetter wrote:
>>>>
>>>>> On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote:
>>>>>>
>>>>>> The framebuffer driver supports programs running full-screen 
>>>>>> directly on
>>>>>> the framebuffer console, such as web browser "links -g", image viewer
>>>>>> "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl",
>>>>>> movie player "mplayer -vo fbdev". The DRM driver doesn't run them.
>>>>>
>>>>> Hm this should in general work on drm drivers. Without that it's 
>>>>> clear the
>>>>> switch-over isn't really ready yet.
>>>>
>>>> I fixed it with this patch two years ago:
>>>> https://lists.freedesktop.org/archives/dri-devel/2018-June/179023.html
>>>>
>>>> But the patch never went through and the fb_defio feature was 
>>>> removed in
>>>> the kernel 5.6 (commit d0c4fc5a4814e431c15272935c8dc973c18073aa).
>>>>
>>>>
>>>> Without fb_defio, the only other possibility how to update the 
>>>> screen is
>>>> the ioctl DRM_IOCTL_MODE_DIRTYFB. But this ioctl requires master 
>>>> mode, so
>>>> user programs like "links -g" can't issue it.
>>>
>>> That's confusing. DIRTYFB is only for DRM.
>>
>> Yes, you're right.
>>
>>> And why can links not run as DRM master mode? If it renders to the 
>>> terminal,
>>> it should act like a composer. In that case it almost certainly wants 
>>> master
>>> status.
>>>
>>> Best regards
>>> Thomas
>>
>> How can a userspace program acquire master mode without being suid?
> 
> For my understanding, there's no easy solution to that. :/
> 
> I guess we (DRM devs) have to treat fbdev as the solution for use cases 
> such as ours.

s/ours/yours

> 
> For the unplug issue, I'll try to reproduce and fix it.
> 
> For the performance problems, we might be able to squeeze a few more 
> cycles out of it.
> 
> Best regards
> Thomas
> 
>>
>> Is there some "Hello World!" program that shows how to use DRM? I'm 
>> not an
>> expert in DRM, but if there were some tutorial+documentation, I could
>> consider porting "links" to it.
>>
>> Mikulas
>>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-12-02  7:55           ` Thomas Zimmermann
  2020-12-02  8:01             ` Thomas Zimmermann
@ 2020-12-02  8:29             ` Pekka Paalanen
  2020-12-02 17:52             ` Daniel Vetter
  2 siblings, 0 replies; 15+ messages in thread
From: Pekka Paalanen @ 2020-12-02  8:29 UTC (permalink / raw)
  To: Mikulas Patocka
  Cc: Thomas Zimmermann, linux-fbdev, geert+renesas, linux-doc,
	daniel.vetter, corbet, bernie, dri-devel, sam

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On Wed, 2 Dec 2020 08:55:52 +0100
Thomas Zimmermann <tzimmermann@suse.de> wrote:

> Hi
> 
> Am 01.12.20 um 12:20 schrieb Mikulas Patocka:
> > 
> > 
> > On Tue, 1 Dec 2020, Thomas Zimmermann wrote:
> >   

...

> >> And why can links not run as DRM master mode? If it renders to the terminal,
> >> it should act like a composer. In that case it almost certainly wants master
> >> status.
> >>
> >> Best regards
> >> Thomas  
> > 
> > How can a userspace program acquire master mode without being suid?  
> 
> For my understanding, there's no easy solution to that. :/

Hi,

there are several ways, though whether they are "easy" depends on your
mindset.

The best thing is to connect to logind D-Bus API and ask that for
session control, set up your session, and logind will open all input
and DRM devices for you, and logind will even handle most of the
complicated setup, DRM master and VT-switching for you.

Or, if no-one else has the DRM device open and you open it, you
automatically become DRM master. AFAIU, after recent kernel changes, it
is even possible to use dropMaster and setMaster after this without
being root, as long as you once in the file description lifetime had
DRM master.

Since this is about switching from fbdev to KMS API, you already have
all the tricky, complicated, arcane code to deal with tty setup and
VT-switching.

However, doing all that patching to all apps you want to use is such an
effort, that I'd ask if it would not be easier to just run a
light-weight Wayland compositor and run your apps in Wayland mode. Of
course, that requires choosing apps that run on Wayland to begin with,
so maybe it's not for you.


Thanks,
pq

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^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH] fbdev: Remove udlfb driver
  2020-12-02  7:55           ` Thomas Zimmermann
  2020-12-02  8:01             ` Thomas Zimmermann
  2020-12-02  8:29             ` Pekka Paalanen
@ 2020-12-02 17:52             ` Daniel Vetter
  2 siblings, 0 replies; 15+ messages in thread
From: Daniel Vetter @ 2020-12-02 17:52 UTC (permalink / raw)
  To: Thomas Zimmermann
  Cc: Mikulas Patocka, Linux Fbdev development list,
	Geert Uytterhoeven, Jonathan Corbet, Linux Doc Mailing List,
	Bernie Thompson, dri-devel, Sam Ravnborg

On Wed, Dec 2, 2020 at 8:55 AM Thomas Zimmermann <tzimmermann@suse.de> wrote:
>
> Hi
>
> Am 01.12.20 um 12:20 schrieb Mikulas Patocka:
> >
> >
> > On Tue, 1 Dec 2020, Thomas Zimmermann wrote:
> >
> >> Hi
> >>
> >> Am 30.11.20 um 19:39 schrieb Mikulas Patocka:
> >>>
> >>>
> >>> On Mon, 30 Nov 2020, Daniel Vetter wrote:
> >>>
> >>>> On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote:
> >>>>>
> >>>>> The framebuffer driver supports programs running full-screen directly on
> >>>>> the framebuffer console, such as web browser "links -g", image viewer
> >>>>> "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl",
> >>>>> movie player "mplayer -vo fbdev". The DRM driver doesn't run them.
> >>>>
> >>>> Hm this should in general work on drm drivers. Without that it's clear the
> >>>> switch-over isn't really ready yet.
> >>>
> >>> I fixed it with this patch two years ago:
> >>> https://lists.freedesktop.org/archives/dri-devel/2018-June/179023.html
> >>>
> >>> But the patch never went through and the fb_defio feature was removed in
> >>> the kernel 5.6 (commit d0c4fc5a4814e431c15272935c8dc973c18073aa).
> >>>
> >>>
> >>> Without fb_defio, the only other possibility how to update the screen is
> >>> the ioctl DRM_IOCTL_MODE_DIRTYFB. But this ioctl requires master mode, so
> >>> user programs like "links -g" can't issue it.
> >>
> >> That's confusing. DIRTYFB is only for DRM.
> >
> > Yes, you're right.
> >
> >> And why can links not run as DRM master mode? If it renders to the terminal,
> >> it should act like a composer. In that case it almost certainly wants master
> >> status.
> >>
> >> Best regards
> >> Thomas
> >
> > How can a userspace program acquire master mode without being suid?
>
> For my understanding, there's no easy solution to that. :/

If you're absolutely the only thing running, the first one to open the
card* node wins. But usually you have something like logind managing
this for you (for vt switching), since ad-hoc this is a very fragile
scheme.

I'm not exactly sure how logind gives you an already opened drm device
in master mode, that's a bit tricky. Without either being suid root or
participating in the logind scheme you won't be able to vt switch
though.

But bare metal kms usage should work I as-is.
-Daniel

>
> I guess we (DRM devs) have to treat fbdev as the solution for use cases
> such as ours.
>
> For the unplug issue, I'll try to reproduce and fix it.
>
> For the performance problems, we might be able to squeeze a few more
> cycles out of it.
>
> Best regards
> Thomas
>
> >
> > Is there some "Hello World!" program that shows how to use DRM? I'm not an
> > expert in DRM, but if there were some tutorial+documentation, I could
> > consider porting "links" to it.
> >
> > Mikulas
> >
>
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Maxfeldstr. 5, 90409 Nürnberg, Germany
> (HRB 36809, AG Nürnberg)
> Geschäftsführer: Felix Imendörffer
>


-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

^ permalink raw reply	[flat|nested] 15+ messages in thread

end of thread, other threads:[~2020-12-02 17:52 UTC | newest]

Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-11-30 12:52 [PATCH] fbdev: Remove udlfb driver Thomas Zimmermann
2020-11-30 14:31 ` Mikulas Patocka
2020-11-30 15:41   ` Daniel Vetter
2020-11-30 18:39     ` Mikulas Patocka
2020-11-30 21:06       ` Daniel Vetter
2020-12-01 11:26         ` Mikulas Patocka
2020-12-01  8:07       ` Thomas Zimmermann
2020-12-01 11:20         ` Mikulas Patocka
2020-12-02  7:55           ` Thomas Zimmermann
2020-12-02  8:01             ` Thomas Zimmermann
2020-12-02  8:29             ` Pekka Paalanen
2020-12-02 17:52             ` Daniel Vetter
2020-12-01  8:02   ` Thomas Zimmermann
2020-12-01 10:44     ` Mikulas Patocka
2020-12-01 20:09       ` Mikulas Patocka

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