diff options
Diffstat (limited to 'drivers/gpu/drm/mgag200')
-rw-r--r-- | drivers/gpu/drm/mgag200/Kconfig | 12 | ||||
-rw-r--r-- | drivers/gpu/drm/mgag200/mgag200_drv.c | 26 | ||||
-rw-r--r-- | drivers/gpu/drm/mgag200/mgag200_mode.c | 22 |
3 files changed, 51 insertions, 9 deletions
diff --git a/drivers/gpu/drm/mgag200/Kconfig b/drivers/gpu/drm/mgag200/Kconfig index b28c5e4828f4..5e4d48df4854 100644 --- a/drivers/gpu/drm/mgag200/Kconfig +++ b/drivers/gpu/drm/mgag200/Kconfig @@ -11,3 +11,15 @@ config DRM_MGAG200 MGA G200 desktop chips and the server variants. It requires 0.3.0 of the modesetting userspace driver, and a version of mga driver that will fail on KMS enabled devices. + +config DRM_MGAG200_IOBURST_WORKAROUND + bool "Disable buffer caching" + depends on DRM_MGAG200 && PREEMPT_RT && X86 + help + Enable a workaround to avoid I/O bursts within the mgag200 driver at + the expense of overall display performance. + It restores the <v5.10 behavior, by mapping the framebuffer in system + RAM as Write-Combining, and flushing the cache after each write. + This is only useful on x86_64 if you want to run processes with + deterministic latency. + If unsure, say N. diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c index 2fb18b782b05..573dbe256aa8 100644 --- a/drivers/gpu/drm/mgag200/mgag200_drv.c +++ b/drivers/gpu/drm/mgag200/mgag200_drv.c @@ -84,6 +84,20 @@ resource_size_t mgag200_probe_vram(void __iomem *mem, resource_size_t size) return offset - 65536; } +#if defined(CONFIG_DRM_MGAG200_IOBURST_WORKAROUND) +static struct drm_gem_object *mgag200_create_object(struct drm_device *dev, size_t size) +{ + struct drm_gem_shmem_object *shmem; + + shmem = kzalloc(sizeof(*shmem), GFP_KERNEL); + if (!shmem) + return NULL; + + shmem->map_wc = true; + return &shmem->base; +} +#endif + /* * DRM driver */ @@ -99,6 +113,9 @@ static const struct drm_driver mgag200_driver = { .major = DRIVER_MAJOR, .minor = DRIVER_MINOR, .patchlevel = DRIVER_PATCHLEVEL, +#if defined(CONFIG_DRM_MGAG200_IOBURST_WORKAROUND) + .gem_create_object = mgag200_create_object, +#endif DRM_GEM_SHMEM_DRIVER_OPS, }; @@ -146,14 +163,13 @@ int mgag200_device_preinit(struct mga_device *mdev) } mdev->vram_res = res; - /* Don't fail on errors, but performance might be reduced. */ - devm_arch_io_reserve_memtype_wc(dev->dev, res->start, resource_size(res)); - devm_arch_phys_wc_add(dev->dev, res->start, resource_size(res)); - - mdev->vram = devm_ioremap(dev->dev, res->start, resource_size(res)); + mdev->vram = devm_ioremap_wc(dev->dev, res->start, resource_size(res)); if (!mdev->vram) return -ENOMEM; + /* Don't fail on errors, but performance might be reduced. */ + devm_arch_phys_wc_add(dev->dev, res->start, resource_size(res)); + return 0; } diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c index 0f0d59938c3a..e17cb4c5f774 100644 --- a/drivers/gpu/drm/mgag200/mgag200_mode.c +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c @@ -13,14 +13,15 @@ #include <drm/drm_atomic.h> #include <drm/drm_atomic_helper.h> +#include <drm/drm_cache.h> #include <drm/drm_damage_helper.h> +#include <drm/drm_edid.h> #include <drm/drm_format_helper.h> #include <drm/drm_fourcc.h> #include <drm/drm_framebuffer.h> #include <drm/drm_gem_atomic_helper.h> #include <drm/drm_gem_framebuffer_helper.h> #include <drm/drm_print.h> -#include <drm/drm_probe_helper.h> #include "mgag200_drv.h" @@ -436,6 +437,13 @@ static void mgag200_handle_damage(struct mga_device *mdev, const struct iosys_ma iosys_map_incr(&dst, drm_fb_clip_offset(fb->pitches[0], fb->format, clip)); drm_fb_memcpy(&dst, fb->pitches, vmap, fb, clip); + + /* Flushing the cache greatly improves latency on x86_64 */ +#if defined(CONFIG_DRM_MGAG200_IOBURST_WORKAROUND) + if (!vmap->is_iomem) + drm_clflush_virt_range(vmap->vaddr + clip->y1 * fb->pitches[0], + drm_rect_height(clip) * fb->pitches[0]); +#endif } /* @@ -717,17 +725,23 @@ void mgag200_crtc_atomic_destroy_state(struct drm_crtc *crtc, struct drm_crtc_st int mgag200_vga_connector_helper_get_modes(struct drm_connector *connector) { struct mga_device *mdev = to_mga_device(connector->dev); - int ret; + const struct drm_edid *drm_edid; + int count; /* * Protect access to I/O registers from concurrent modesetting * by acquiring the I/O-register lock. */ mutex_lock(&mdev->rmmio_lock); - ret = drm_connector_helper_get_modes_from_ddc(connector); + + drm_edid = drm_edid_read(connector); + drm_edid_connector_update(connector, drm_edid); + count = drm_edid_connector_add_modes(connector); + drm_edid_free(drm_edid); + mutex_unlock(&mdev->rmmio_lock); - return ret; + return count; } /* |