![Gabriel Krisman Bertazi](/assets/img/avatar_default.png)
If fbdev registration fails for whatever reason, the error path of bochs_fbdev_init() will call bochs_fbdev_fini(), but since an fbdev initialization error is not fatal to the probe function, a subsequent device removal will try to call bochs_fbdev_fini() again, hitting the Oops below. This was detected by 0-day with a failing framebuffer registration and CONFIG_DEBUG_TEST_DRIVER_REMOVE=y. This reproduces the scenario I mentioned above at insmod time, because the test attempts to remove the device right after probing. root@debian:~# insmod bochs-drm.ko [ 17.609635] [drm] Found bochs VGA, ID 0xb0c0. [ 17.612974] [drm] Framebuffer size 16384 kB @ 0xfa000000, mmio @ 0xfebf2000. [ 17.613938] [TTM] Zone kernel: Available graphics memory: 1022244 kiB [ 17.614701] [TTM] Initializing pool allocator [ 17.615427] [TTM] Initializing DMA pool allocator [ 17.619143] fbcon: bochsdrmfb (fb0) is primary device [ 17.619428] Console: switching to colour frame buffer device 128x48 [ 17.621047] bochs-drm 0000:00:02.0: fb0: bochsdrmfb frame buffer device [ 17.641111] [drm] Initialized bochs-drm 1.0.0 20130925 for 0000:00:02.0 on minor 0 [ 17.642380] general protection fault: 0000 [#1] SMP [ 17.642985] Modules linked in: bochs_drm(+) [ 17.643259] CPU: 4 PID: 3279 Comm: insmod Tainted: G W 4.11.0-rc1+ #119 [ 17.643259] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014 [ 17.643259] task: ffff88007af35e00 task.stack: ffffc90000d84000 [ 17.643259] RIP: 0010:drm_fb_helper_fini+0x8e/0x110 [ 17.643259] RSP: 0018:ffffc90000d87ad0 EFLAGS: 00010202 [ 17.643259] RAX: dead000000000200 RBX: ffff8800790d5770 RCX: 0000000000000000 [ 17.652101] RDX: dead000000000100 RSI: 000000007fffffff RDI: ffffffff81eaf820 [ 17.652101] RBP: ffffc90000d87ae0 R08: 0000000000000000 R09: ffff88007271d918 [ 17.652101] R10: ffffc90000d87a88 R11: 0000000000000000 R12: 0000000000000000 [ 17.652101] R13: ffff8800790d56d0 R14: 0000000000000000 R15: 0000000000000000 [ 17.652101] FS: 00007f9285995700(0000) GS:ffff88007cf00000(0000) knlGS:0000000000000000 [ 17.652101] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 17.652101] CR2: 0000564f1cf9f1e8 CR3: 0000000079686000 CR4: 00000000000006e0 [ 17.652101] Call Trace: [ 17.652101] bochs_fbdev_fini+0x24/0x90 [bochs_drm] [ 17.652101] bochs_unload+0x16/0x50 [bochs_drm] [ 17.652101] drm_dev_unregister+0x37/0xd0 [ 17.652101] drm_put_dev+0x31/0x60 [ 17.652101] bochs_pci_remove+0x10/0x20 [bochs_drm] [ 17.652101] pci_device_remove+0x34/0xb0 [ 17.652101] driver_probe_device+0xd0/0x370 [ 17.652101] __driver_attach+0x96/0xa0 [ 17.652101] ? driver_probe_device+0x370/0x370 [ 17.652101] bus_for_each_dev+0x5b/0x90 [ 17.652101] driver_attach+0x19/0x20 [ 17.652101] bus_add_driver+0x11c/0x220 [ 17.652101] driver_register+0x5b/0xd0 [ 17.652101] ? 0xffffffffa0006000 [ 17.652101] __pci_register_driver+0x47/0x50 [ 17.652101] drm_pci_init+0xe1/0xf0 [ 17.652101] ? 0xffffffffa0006000 [ 17.652101] bochs_init+0x3c/0x1000 [bochs_drm] [ 17.652101] do_one_initcall+0x3e/0x180 [ 17.652101] ? kmem_cache_alloc_trace+0x33/0x150 [ 17.652101] do_init_module+0x5a/0x1eb [ 17.652101] load_module+0x1ea0/0x2650 [ 17.652101] ? __symbol_put+0x40/0x40 [ 17.652101] ? kernel_read_file+0x19e/0x1c0 [ 17.652101] ? kernel_read_file_from_fd+0x44/0x70 [ 17.652101] SYSC_finit_module+0xba/0xc0 [ 17.652101] SyS_finit_module+0x9/0x10 [ 17.652101] entry_SYSCALL_64_fastpath+0x1a/0xa9 [ 17.652101] RIP: 0033:0x7f92854da119 [ 17.652101] RSP: 002b:00007ffcd0390498 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 [ 17.652101] RAX: ffffffffffffffda RBX: 00007f928578eb58 RCX: 00007f92854da119 [ 17.652101] RDX: 0000000000000000 RSI: 0000564f1c8bd638 RDI: 0000000000000003 [ 17.652101] RBP: 000000000000270e R08: 0000000000000000 R09: 00007f9285790ea0 [ 17.652101] R10: 0000000000000003 R11: 0000000000000246 R12: 00007f928578eb58 [ 17.652101] R13: 0000000000001020 R14: 0000564f1cf9e1c0 R15: 00007f928578eb00 [ 17.652101] Code: c7 20 f8 ea 81 e8 b3 3e 50 00 48 8b 83 d0 00 00 00 48 8d 93 d0 00 00 00 48 39 c2 74 46 48 8b 83 d8 00 00 00 48 8b 93 d0 00 00 00 <48> 89 42 08 48 89 10 48 b8 00 01 00 00 0000 ad de 48 89 83 d0 [ 17.652101] RIP: drm_fb_helper_fini+0x8e/0x110 RSP: ffffc90000d87ad0 [ 17.653331] ---[ end trace 542fd75a2e60a6a4 ]--- Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/20170324045444.11912-1-krisman@collabora.co.uk Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
200 lines
4.6 KiB
C
200 lines
4.6 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include "bochs.h"
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/* ---------------------------------------------------------------------- */
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static int bochsfb_mmap(struct fb_info *info,
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struct vm_area_struct *vma)
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{
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struct drm_fb_helper *fb_helper = info->par;
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struct bochs_device *bochs =
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container_of(fb_helper, struct bochs_device, fb.helper);
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struct bochs_bo *bo = gem_to_bochs_bo(bochs->fb.gfb.obj);
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return ttm_fbdev_mmap(vma, &bo->bo);
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}
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static struct fb_ops bochsfb_ops = {
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.owner = THIS_MODULE,
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DRM_FB_HELPER_DEFAULT_OPS,
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.fb_fillrect = drm_fb_helper_sys_fillrect,
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.fb_copyarea = drm_fb_helper_sys_copyarea,
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.fb_imageblit = drm_fb_helper_sys_imageblit,
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.fb_mmap = bochsfb_mmap,
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};
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static int bochsfb_create_object(struct bochs_device *bochs,
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const struct drm_mode_fb_cmd2 *mode_cmd,
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struct drm_gem_object **gobj_p)
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{
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struct drm_device *dev = bochs->dev;
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struct drm_gem_object *gobj;
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u32 size;
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int ret = 0;
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size = mode_cmd->pitches[0] * mode_cmd->height;
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ret = bochs_gem_create(dev, size, true, &gobj);
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if (ret)
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return ret;
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*gobj_p = gobj;
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return ret;
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}
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static int bochsfb_create(struct drm_fb_helper *helper,
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struct drm_fb_helper_surface_size *sizes)
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{
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struct bochs_device *bochs =
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container_of(helper, struct bochs_device, fb.helper);
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struct fb_info *info;
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struct drm_framebuffer *fb;
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struct drm_mode_fb_cmd2 mode_cmd;
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struct drm_gem_object *gobj = NULL;
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struct bochs_bo *bo = NULL;
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int size, ret;
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if (sizes->surface_bpp != 32)
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return -EINVAL;
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mode_cmd.width = sizes->surface_width;
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mode_cmd.height = sizes->surface_height;
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mode_cmd.pitches[0] = mode_cmd.width * ((sizes->surface_bpp + 7) / 8);
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mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
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sizes->surface_depth);
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size = mode_cmd.pitches[0] * mode_cmd.height;
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/* alloc, pin & map bo */
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ret = bochsfb_create_object(bochs, &mode_cmd, &gobj);
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if (ret) {
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DRM_ERROR("failed to create fbcon backing object %d\n", ret);
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return ret;
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}
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bo = gem_to_bochs_bo(gobj);
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ret = ttm_bo_reserve(&bo->bo, true, false, NULL);
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if (ret)
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return ret;
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ret = bochs_bo_pin(bo, TTM_PL_FLAG_VRAM, NULL);
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if (ret) {
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DRM_ERROR("failed to pin fbcon\n");
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ttm_bo_unreserve(&bo->bo);
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return ret;
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}
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ret = ttm_bo_kmap(&bo->bo, 0, bo->bo.num_pages,
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&bo->kmap);
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if (ret) {
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DRM_ERROR("failed to kmap fbcon\n");
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ttm_bo_unreserve(&bo->bo);
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return ret;
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}
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ttm_bo_unreserve(&bo->bo);
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/* init fb device */
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info = drm_fb_helper_alloc_fbi(helper);
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if (IS_ERR(info))
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return PTR_ERR(info);
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info->par = &bochs->fb.helper;
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ret = bochs_framebuffer_init(bochs->dev, &bochs->fb.gfb, &mode_cmd, gobj);
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if (ret)
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return ret;
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bochs->fb.size = size;
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/* setup helper */
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fb = &bochs->fb.gfb.base;
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bochs->fb.helper.fb = fb;
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strcpy(info->fix.id, "bochsdrmfb");
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info->flags = FBINFO_DEFAULT;
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info->fbops = &bochsfb_ops;
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drm_fb_helper_fill_fix(info, fb->pitches[0], fb->format->depth);
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drm_fb_helper_fill_var(info, &bochs->fb.helper, sizes->fb_width,
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sizes->fb_height);
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info->screen_base = bo->kmap.virtual;
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info->screen_size = size;
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drm_vma_offset_remove(&bo->bo.bdev->vma_manager, &bo->bo.vma_node);
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info->fix.smem_start = 0;
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info->fix.smem_len = size;
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bochs->fb.initialized = true;
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return 0;
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}
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static int bochs_fbdev_destroy(struct bochs_device *bochs)
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{
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struct bochs_framebuffer *gfb = &bochs->fb.gfb;
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DRM_DEBUG_DRIVER("\n");
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drm_fb_helper_unregister_fbi(&bochs->fb.helper);
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if (gfb->obj) {
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drm_gem_object_unreference_unlocked(gfb->obj);
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gfb->obj = NULL;
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}
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drm_framebuffer_unregister_private(&gfb->base);
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drm_framebuffer_cleanup(&gfb->base);
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return 0;
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}
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static const struct drm_fb_helper_funcs bochs_fb_helper_funcs = {
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.fb_probe = bochsfb_create,
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};
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int bochs_fbdev_init(struct bochs_device *bochs)
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{
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int ret;
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drm_fb_helper_prepare(bochs->dev, &bochs->fb.helper,
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&bochs_fb_helper_funcs);
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ret = drm_fb_helper_init(bochs->dev, &bochs->fb.helper, 1);
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if (ret)
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return ret;
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ret = drm_fb_helper_single_add_all_connectors(&bochs->fb.helper);
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if (ret)
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goto fini;
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drm_helper_disable_unused_functions(bochs->dev);
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ret = drm_fb_helper_initial_config(&bochs->fb.helper, 32);
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if (ret)
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goto fini;
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return 0;
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fini:
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drm_fb_helper_fini(&bochs->fb.helper);
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return ret;
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}
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void bochs_fbdev_fini(struct bochs_device *bochs)
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{
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if (bochs->fb.initialized)
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bochs_fbdev_destroy(bochs);
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if (bochs->fb.helper.fbdev)
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drm_fb_helper_fini(&bochs->fb.helper);
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bochs->fb.initialized = false;
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}
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