mirror of https://gitee.com/openkylin/linux.git
68a958a915
The udlfb driver maintained an open count and cleaned up itself when the count reached zero. But the console is also counted in the reference count - so, if the user unplugged the device, the open count would not drop to zero and the driver stayed loaded with console attached. If the user re-plugged the adapter, it would create a device /dev/fb1, show green screen and the access to the console would be lost. The framebuffer subsystem has reference counting on its own - in order to fix the unplug bug, we rely the framebuffer reference counting. When the user unplugs the adapter, we call unregister_framebuffer unconditionally. unregister_framebuffer will unbind the console, wait until all users stop using the framebuffer and then call the fb_destroy method. The fb_destroy cleans up the USB driver. This patch makes the following changes: * Drop dlfb->kref and rely on implicit framebuffer reference counting instead. * dlfb_usb_disconnect calls unregister_framebuffer, the rest of driver cleanup is done in the function dlfb_ops_destroy. dlfb_ops_destroy will be called by the framebuffer subsystem when no processes have the framebuffer open or mapped. * We don't use workqueue during initialization, but initialize directly from dlfb_usb_probe. The workqueue could race with dlfb_usb_disconnect and this racing would produce various kinds of memory corruption. * We use usb_get_dev and usb_put_dev to make sure that the USB subsystem doesn't free the device under us. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> cc: Dave Airlie <airlied@redhat.com> Cc: Bernie Thompson <bernie@plugable.com>, Cc: Ladislav Michl <ladis@linux-mips.org> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> |
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| .. | ||
| atmel_lcdc.h | ||
| aty128.h | ||
| broadsheetfb.h | ||
| cirrus.h | ||
| cvisionppc.h | ||
| da8xx-fb.h | ||
| display_timing.h | ||
| edid.h | ||
| gbe.h | ||
| hecubafb.h | ||
| ili9320.h | ||
| imx-ipu-image-convert.h | ||
| imx-ipu-v3.h | ||
| kyro.h | ||
| mach64.h | ||
| maxinefb.h | ||
| mbxfb.h | ||
| metronomefb.h | ||
| mipi_display.h | ||
| mmp_disp.h | ||
| neomagic.h | ||
| newport.h | ||
| of_display_timing.h | ||
| of_videomode.h | ||
| omap-panel-data.h | ||
| omapfb_dss.h | ||
| omapvrfb.h | ||
| permedia2.h | ||
| platform_lcd.h | ||
| pm3fb.h | ||
| pmag-ba-fb.h | ||
| pmagb-b-fb.h | ||
| pxa168fb.h | ||
| radeon.h | ||
| s1d13xxxfb.h | ||
| sa1100fb.h | ||
| samsung_fimd.h | ||
| sh_mobile_lcdc.h | ||
| sisfb.h | ||
| sstfb.h | ||
| tdfx.h | ||
| tgafb.h | ||
| trident.h | ||
| udlfb.h | ||
| uvesafb.h | ||
| vga.h | ||
| videomode.h | ||
| w100fb.h | ||