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Commit 1f692a14 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Dave Airlie
Browse files

drm/i810: remove the BKL 



SMP i810 systems were practically nonexistent and the configuration
was not officially supported by Intel at the time when Pentium-III
was common.

With this change, it is still possible to build a distribution kernel
that has support for SMP and includes the i810 driver without the BKL.
As a precaution, check for the theoretical SMP case at run time and
refuse to load the driver.

We also need to disable CONFIG_PREEMPT builds for this driver.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 7f506847

drivers/gpu/drm/Kconfig

+2 −2
Original line number Diff line number Diff line
@@ -73,8 +73,8 @@ source "drivers/gpu/drm/radeon/Kconfig" 


config DRM_I810

	tristate "Intel I810"

	# BKL usage in order to avoid AB-BA deadlocks, may become BROKEN_ON_SMP

	depends on DRM && AGP && AGP_INTEL && BKL

	# !PREEMPT because of missing ioctl locking

	depends on DRM && AGP && AGP_INTEL && (!PREEMPT || BROKEN)

	help

	  Choose this option if you have an Intel I810 graphics card.  If M is

	  selected, the module will be called i810.  AGP support is required

drivers/gpu/drm/i810/i810_dma.c

+1 −17
Original line number Diff line number Diff line
@@ -37,7 +37,6 @@ 
#include <linux/interrupt.h>	/* For task queue support */

#include <linux/delay.h>

#include <linux/slab.h>

#include <linux/smp_lock.h>

#include <linux/pagemap.h>



#define I810_BUF_FREE		2
@@ -94,7 +93,6 @@ static int i810_mmap_buffers(struct file *filp, struct vm_area_struct *vma) 
	struct drm_buf *buf;

	drm_i810_buf_priv_t *buf_priv;



	lock_kernel();

	dev = priv->minor->dev;

	dev_priv = dev->dev_private;

	buf = dev_priv->mmap_buffer;
@@ -104,7 +102,6 @@ static int i810_mmap_buffers(struct file *filp, struct vm_area_struct *vma) 
	vma->vm_file = filp;



	buf_priv->currently_mapped = I810_BUF_MAPPED;

	unlock_kernel();



	if (io_remap_pfn_range(vma, vma->vm_start,

			       vma->vm_pgoff,
@@ -116,7 +113,7 @@ static int i810_mmap_buffers(struct file *filp, struct vm_area_struct *vma) 
static const struct file_operations i810_buffer_fops = {

	.open = drm_open,

	.release = drm_release,

	.unlocked_ioctl = i810_ioctl,

	.unlocked_ioctl = drm_ioctl,

	.mmap = i810_mmap_buffers,

	.fasync = drm_fasync,

	.llseek = noop_llseek,
@@ -1242,19 +1239,6 @@ int i810_driver_dma_quiescent(struct drm_device *dev) 
	return 0;

}



/*

 * call the drm_ioctl under the big kernel lock because

 * to lock against the i810_mmap_buffers function.

 */

long i810_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

{

	int ret;

	lock_kernel();

	ret = drm_ioctl(file, cmd, arg);

	unlock_kernel();

	return ret;

}



struct drm_ioctl_desc i810_ioctls[] = {

	DRM_IOCTL_DEF_DRV(I810_INIT, i810_dma_init, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY|DRM_UNLOCKED),

	DRM_IOCTL_DEF_DRV(I810_VERTEX, i810_dma_vertex, DRM_AUTH|DRM_UNLOCKED),

drivers/gpu/drm/i810/i810_drv.c

+5 −1
Original line number Diff line number Diff line
@@ -57,7 +57,7 @@ static struct drm_driver driver = { 
		 .owner = THIS_MODULE,

		 .open = drm_open,

		 .release = drm_release,

		 .unlocked_ioctl = i810_ioctl,

		 .unlocked_ioctl = drm_ioctl,

		 .mmap = drm_mmap,

		 .poll = drm_poll,

		 .fasync = drm_fasync,
@@ -79,6 +79,10 @@ static struct drm_driver driver = { 


static int __init i810_init(void)

{

	if (num_possible_cpus() > 1) {

		pr_err("drm/i810 does not support SMP\n");

		return -EINVAL;

	}

	driver.num_ioctls = i810_max_ioctl;

	return drm_init(&driver);

}