-----Original Message----- From: Thomas Zimmermann [mailto:tzimmermann@suse.de] Sent: Monday, September 20, 2021 4:17 PM To: Kuo-Hsiang Chou kuohsiang_chou@aspeedtech.com; dri-devel@lists.freedesktop.org; linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/ast: Atomic CR/SR reg R/W
Hi
Am 17.09.21 um 09:22 schrieb KuoHsiang Chou:
- Avoid IO-index racing
- IO-index racing happened on resolustion switching and mouse moving at the same time
- System hung while IO-index racing occurred.
I'd say that there's something else going one here. Mode setting and cursor movement should be protected against each other by DRM locking. Changing these low-level functions would not solve the issues. I'll try to reproduce the problem ASAP.
Hi Thomas,
Sorry to interrupt you again! May I understand the review's situation? Thanks!
Best Regards, Kuo-Hsiang Chou
Best regards Thomas
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
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Felix Imendörffer