drm/ast: Turn ioregs_lock to modeset_lock

The lock for the I/O registers is only relevant during mode-setting
operations. It protects the registers from concurrent access from
reading EDID information.

Reduce lock coverage to mode setting, rename the lock and move it
entirely into the mode-setting code. No functional changes, as the
I/O lock was never used for anything else than mode setting.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231116100240.22975-2-tzimmermann@suse.de

diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h
index 772f3b049c1694408d7acc89f4235a1c8c657ea9..2ec29480939d398e604f875d2a4d4abc338f4749 100644 (file)
--- a/drivers/gpu/drm/ast/ast_drv.h
+++ b/drivers/gpu/drm/ast/ast_drv.h
@@ -192,7 +192,6 @@ to_ast_bmc_connector(struct drm_connector *connector)
 struct ast_device {
        struct drm_device base;
 
-       struct mutex ioregs_lock; /* Protects access to I/O registers in ioregs */
        void __iomem *regs;
        void __iomem *ioregs;
        void __iomem *dp501_fw_buf;
@@ -207,6 +206,8 @@ struct ast_device {
        unsigned long   vram_size;
        unsigned long   vram_fb_available;
 
+       struct mutex modeset_lock; /* Protects access to modeset I/O registers in ioregs */
+
        struct ast_plane primary_plane;
        struct ast_plane cursor_plane;
        struct drm_crtc crtc;

diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index f4ab40e22ceaca9c3496360b60213c5a2e341a8d..445cf47871a43b135a1179866557ddd7252d9173 100644 (file)
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -440,10 +440,6 @@ struct ast_device *ast_device_create(const struct drm_driver *drv,
 
        pci_set_drvdata(pdev, dev);
 
-       ret = drmm_mutex_init(dev, &ast->ioregs_lock);
-       if (ret)
-               return ERR_PTR(ret);
-
        ast->regs = pcim_iomap(pdev, 1, 0);
        if (!ast->regs)
                return ERR_PTR(-EIO);

diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index c20534d0ef7c8af580e4e6a3eb2c4c2bd49842eb..a718646a66b8fd519b255783204bd0ca77228e33 100644 (file)
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -1358,13 +1358,13 @@ static int ast_vga_connector_helper_get_modes(struct drm_connector *connector)
         * Protect access to I/O registers from concurrent modesetting
         * by acquiring the I/O-register lock.
         */
-       mutex_lock(&ast->ioregs_lock);
+       mutex_lock(&ast->modeset_lock);
 
        edid = drm_get_edid(connector, &ast_vga_connector->i2c->adapter);
        if (!edid)
                goto err_mutex_unlock;
 
-       mutex_unlock(&ast->ioregs_lock);
+       mutex_unlock(&ast->modeset_lock);
 
        count = drm_add_edid_modes(connector, edid);
        kfree(edid);
@@ -1372,7 +1372,7 @@ static int ast_vga_connector_helper_get_modes(struct drm_connector *connector)
        return count;
 
 err_mutex_unlock:
-       mutex_unlock(&ast->ioregs_lock);
+       mutex_unlock(&ast->modeset_lock);
 err_drm_connector_update_edid_property:
        drm_connector_update_edid_property(connector, NULL);
        return 0;
@@ -1464,13 +1464,13 @@ static int ast_sil164_connector_helper_get_modes(struct drm_connector *connector
         * Protect access to I/O registers from concurrent modesetting
         * by acquiring the I/O-register lock.
         */
-       mutex_lock(&ast->ioregs_lock);
+       mutex_lock(&ast->modeset_lock);
 
        edid = drm_get_edid(connector, &ast_sil164_connector->i2c->adapter);
        if (!edid)
                goto err_mutex_unlock;
 
-       mutex_unlock(&ast->ioregs_lock);
+       mutex_unlock(&ast->modeset_lock);
 
        count = drm_add_edid_modes(connector, edid);
        kfree(edid);
@@ -1478,7 +1478,7 @@ static int ast_sil164_connector_helper_get_modes(struct drm_connector *connector
        return count;
 
 err_mutex_unlock:
-       mutex_unlock(&ast->ioregs_lock);
+       mutex_unlock(&ast->modeset_lock);
 err_drm_connector_update_edid_property:
        drm_connector_update_edid_property(connector, NULL);
        return 0;
@@ -1670,13 +1670,13 @@ static int ast_astdp_connector_helper_get_modes(struct drm_connector *connector)
         * Protect access to I/O registers from concurrent modesetting
         * by acquiring the I/O-register lock.
         */
-       mutex_lock(&ast->ioregs_lock);
+       mutex_lock(&ast->modeset_lock);
 
        succ = ast_astdp_read_edid(connector->dev, edid);
        if (succ < 0)
                goto err_mutex_unlock;
 
-       mutex_unlock(&ast->ioregs_lock);
+       mutex_unlock(&ast->modeset_lock);
 
        drm_connector_update_edid_property(connector, edid);
        count = drm_add_edid_modes(connector, edid);
@@ -1685,7 +1685,7 @@ static int ast_astdp_connector_helper_get_modes(struct drm_connector *connector)
        return count;
 
 err_mutex_unlock:
-       mutex_unlock(&ast->ioregs_lock);
+       mutex_unlock(&ast->modeset_lock);
        kfree(edid);
 err_drm_connector_update_edid_property:
        drm_connector_update_edid_property(connector, NULL);
@@ -1870,9 +1870,9 @@ static void ast_mode_config_helper_atomic_commit_tail(struct drm_atomic_state *s
         * display modes. Protect access to I/O registers by acquiring
         * the I/O-register lock. Released in atomic_flush().
         */
-       mutex_lock(&ast->ioregs_lock);
+       mutex_lock(&ast->modeset_lock);
        drm_atomic_helper_commit_tail_rpm(state);
-       mutex_unlock(&ast->ioregs_lock);
+       mutex_unlock(&ast->modeset_lock);
 }
 
 static const struct drm_mode_config_helper_funcs ast_mode_config_helper_funcs = {
@@ -1910,6 +1910,10 @@ int ast_mode_config_init(struct ast_device *ast)
        struct drm_connector *physical_connector = NULL;
        int ret;
 
+       ret = drmm_mutex_init(dev, &ast->modeset_lock);
+       if (ret)
+               return ret;
+
        ret = drmm_mode_config_init(dev);
        if (ret)
                return ret;