1. Avoid IO-index racing 2. IO-index racing happened on resolustion switching and mouse moving at the same time 3. System hung while IO-index racing occurred.
Signed-off-by: KuoHsiang Chou kuohsiang_chou@aspeedtech.com --- drivers/gpu/drm/ast/ast_main.c | 48 +++++++++++++++++++++++++--------- 1 file changed, 36 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c index 79a361867..1d8fa70c5 100644 --- a/drivers/gpu/drm/ast/ast_main.c +++ b/drivers/gpu/drm/ast/ast_main.c @@ -41,28 +41,52 @@ void ast_set_index_reg_mask(struct ast_private *ast, uint32_t base, uint8_t index, uint8_t mask, uint8_t val) { - u8 tmp; - ast_io_write8(ast, base, index); - tmp = (ast_io_read8(ast, base + 1) & mask) | val; - ast_set_index_reg(ast, base, index, tmp); + uint16_t volatile usData; + uint8_t volatile jData; + + do { + ast_io_write8(ast, base, index); + usData = ast_io_read16(ast, base); + } while ((uint8_t)(usData) != index); + + jData = (uint8_t)(usData >> 8); + jData &= mask; + jData |= val; + usData = ((uint16_t) jData << 8) | (uint16_t) index; + ast_io_write16(ast, base, usData); }
uint8_t ast_get_index_reg(struct ast_private *ast, uint32_t base, uint8_t index) { - uint8_t ret; - ast_io_write8(ast, base, index); - ret = ast_io_read8(ast, base + 1); - return ret; + uint16_t volatile usData; + uint8_t volatile jData; + + do { + ast_io_write8(ast, base, index); + usData = ast_io_read16(ast, base); + } while ((uint8_t)(usData) != index); + + jData = (uint8_t)(usData >> 8); + + return jData; }
uint8_t ast_get_index_reg_mask(struct ast_private *ast, uint32_t base, uint8_t index, uint8_t mask) { - uint8_t ret; - ast_io_write8(ast, base, index); - ret = ast_io_read8(ast, base + 1) & mask; - return ret; + uint16_t volatile usData; + uint8_t volatile jData; + + do { + ast_io_write8(ast, base, index); + usData = ast_io_read16(ast, base); + } while ((uint8_t)(usData) != index); + + jData = (uint8_t)(usData >> 8); + jData &= mask; + + return jData; }
static void ast_detect_config_mode(struct drm_device *dev, u32 *scu_rev) -- 2.18.4