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drm/ast: Protect concurrent access to I/O registers with lock

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Add a mutex lock to protect concurrent access to I/O registers
against each other. This happens between invocation of commit-
tail functions and get-mode operations. Both with use the CRTC
index register AST_IO_CRTC_PORT. Concurrent access can lead to
failed mode-setting operations.

v2:
	* fix typo in commit description (Jocelyn)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reported-by: KuoHsiang Chou <kuohsiang_chou@aspeedtech.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220502142514.2174-3-tzimmermann@suse.de
This commit is contained in:
Thomas Zimmermann 2022-05-02 16:25:13 +02:00
parent e13f13e039
commit f870231fdd
3 changed files with 50 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/gpu/drm/ast/ast_drv.h
View File

@ -159,6 +159,7 @@ to_ast_sil164_connector(struct drm_connector *connector)
struct ast_private {
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;

4
drivers/gpu/drm/ast/ast_main.c
View File

@ -421,6 +421,10 @@ struct ast_private *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);

48
drivers/gpu/drm/ast/ast_mode.c
View File

@ -1119,6 +1119,20 @@ static int ast_crtc_helper_atomic_check(struct drm_crtc *crtc,
return 0;
}
static void ast_crtc_helper_atomic_begin(struct drm_crtc *crtc, struct drm_atomic_state *state)
{
struct drm_device *dev = crtc->dev;
struct ast_private *ast = to_ast_private(dev);
/*
* Concurrent operations could possibly trigger a call to
* drm_connector_helper_funcs.get_modes by trying to read the
* display modes. Protect access to I/O registers by acquiring
* the I/O-register lock. Released in atomic_flush().
*/
mutex_lock(&ast->ioregs_lock);
}
static void
ast_crtc_helper_atomic_flush(struct drm_crtc *crtc,
struct drm_atomic_state *state)
@ -1127,7 +1141,8 @@ ast_crtc_helper_atomic_flush(struct drm_crtc *crtc,
crtc);
struct drm_crtc_state *old_crtc_state = drm_atomic_get_old_crtc_state(state,
crtc);
struct ast_private *ast = to_ast_private(crtc->dev);
struct drm_device *dev = crtc->dev;
struct ast_private *ast = to_ast_private(dev);
struct ast_crtc_state *ast_crtc_state = to_ast_crtc_state(crtc_state);
struct ast_crtc_state *old_ast_crtc_state = to_ast_crtc_state(old_crtc_state);
struct ast_vbios_mode_info *vbios_mode_info = &ast_crtc_state->vbios_mode_info;
@ -1142,6 +1157,8 @@ ast_crtc_helper_atomic_flush(struct drm_crtc *crtc,
//Set Aspeed Display-Port
if (ast->tx_chip_type == AST_TX_ASTDP)
ast_dp_set_mode(crtc, vbios_mode_info);
mutex_unlock(&ast->ioregs_lock);
}
static void
@ -1200,6 +1217,7 @@ ast_crtc_helper_atomic_disable(struct drm_crtc *crtc,
static const struct drm_crtc_helper_funcs ast_crtc_helper_funcs = {
.mode_valid = ast_crtc_helper_mode_valid,
.atomic_check = ast_crtc_helper_atomic_check,
.atomic_begin = ast_crtc_helper_atomic_begin,
.atomic_flush = ast_crtc_helper_atomic_flush,
.atomic_enable = ast_crtc_helper_atomic_enable,
.atomic_disable = ast_crtc_helper_atomic_disable,
@ -1285,21 +1303,33 @@ static int ast_crtc_init(struct drm_device *dev)
static int ast_vga_connector_helper_get_modes(struct drm_connector *connector)
{
struct ast_vga_connector *ast_vga_connector = to_ast_vga_connector(connector);
struct drm_device *dev = connector->dev;
struct ast_private *ast = to_ast_private(dev);
struct edid *edid;
int count;
if (!ast_vga_connector->i2c)
goto err_drm_connector_update_edid_property;
/*
* Protect access to I/O registers from concurrent modesetting
* by acquiring the I/O-register lock.
*/
mutex_lock(&ast->ioregs_lock);
edid = drm_get_edid(connector, &ast_vga_connector->i2c->adapter);
if (!edid)
goto err_drm_connector_update_edid_property;
goto err_mutex_unlock;
mutex_unlock(&ast->ioregs_lock);
count = drm_add_edid_modes(connector, edid);
kfree(edid);
return count;
err_mutex_unlock:
mutex_unlock(&ast->ioregs_lock);
err_drm_connector_update_edid_property:
drm_connector_update_edid_property(connector, NULL);
return 0;
@ -1379,21 +1409,33 @@ static int ast_vga_output_init(struct ast_private *ast)
static int ast_sil164_connector_helper_get_modes(struct drm_connector *connector)
{
struct ast_sil164_connector *ast_sil164_connector = to_ast_sil164_connector(connector);
struct drm_device *dev = connector->dev;
struct ast_private *ast = to_ast_private(dev);
struct edid *edid;
int count;
if (!ast_sil164_connector->i2c)
goto err_drm_connector_update_edid_property;
/*
* Protect access to I/O registers from concurrent modesetting
* by acquiring the I/O-register lock.
*/
mutex_lock(&ast->ioregs_lock);
edid = drm_get_edid(connector, &ast_sil164_connector->i2c->adapter);
if (!edid)
goto err_drm_connector_update_edid_property;
goto err_mutex_unlock;
mutex_unlock(&ast->ioregs_lock);
count = drm_add_edid_modes(connector, edid);
kfree(edid);
return count;
err_mutex_unlock:
mutex_unlock(&ast->ioregs_lock);
err_drm_connector_update_edid_property:
drm_connector_update_edid_property(connector, NULL);
return 0;