From 4ccc28f725bc2b7b0a3bc27e9c15f4eaf63fb812 Mon Sep 17 00:00:00 2001 From: Roel Kluin Date: Tue, 5 May 2009 08:39:24 +0200 Subject: [PATCH 1/3] i2c: Timeouts off by 1 with while (timeout++ < MAX_TIMEOUT); timeout reaches MAX_TIMEOUT + 1 after the loop, so the tests below are off by one. Signed-off-by: Roel Kluin Signed-off-by: Jean Delvare --- drivers/i2c/busses/i2c-ali1535.c | 2 +- drivers/i2c/busses/i2c-ali15x3.c | 2 +- drivers/i2c/busses/i2c-amd756.c | 4 ++-- drivers/i2c/busses/i2c-i801.c | 8 ++++---- drivers/i2c/busses/i2c-isch.c | 2 +- drivers/i2c/busses/i2c-nforce2.c | 2 +- drivers/i2c/busses/i2c-sis5595.c | 2 +- drivers/i2c/busses/i2c-sis630.c | 2 +- drivers/i2c/busses/i2c-sis96x.c | 2 +- 9 files changed, 13 insertions(+), 13 deletions(-) diff --git a/drivers/i2c/busses/i2c-ali1535.c b/drivers/i2c/busses/i2c-ali1535.c index 981e080b32a..d108450df06 100644 --- a/drivers/i2c/busses/i2c-ali1535.c +++ b/drivers/i2c/busses/i2c-ali1535.c @@ -284,7 +284,7 @@ static int ali1535_transaction(struct i2c_adapter *adap) && (timeout++ < MAX_TIMEOUT)); /* If the SMBus is still busy, we give up */ - if (timeout >= MAX_TIMEOUT) { + if (timeout > MAX_TIMEOUT) { result = -ETIMEDOUT; dev_err(&adap->dev, "SMBus Timeout!\n"); } diff --git a/drivers/i2c/busses/i2c-ali15x3.c b/drivers/i2c/busses/i2c-ali15x3.c index 39066dee46e..d627fceb790 100644 --- a/drivers/i2c/busses/i2c-ali15x3.c +++ b/drivers/i2c/busses/i2c-ali15x3.c @@ -306,7 +306,7 @@ static int ali15x3_transaction(struct i2c_adapter *adap) && (timeout++ < MAX_TIMEOUT)); /* If the SMBus is still busy, we give up */ - if (timeout >= MAX_TIMEOUT) { + if (timeout > MAX_TIMEOUT) { result = -ETIMEDOUT; dev_err(&adap->dev, "SMBus Timeout!\n"); } diff --git a/drivers/i2c/busses/i2c-amd756.c b/drivers/i2c/busses/i2c-amd756.c index 220f4a1eee1..f7d6fe9c49b 100644 --- a/drivers/i2c/busses/i2c-amd756.c +++ b/drivers/i2c/busses/i2c-amd756.c @@ -126,7 +126,7 @@ static int amd756_transaction(struct i2c_adapter *adap) } while ((temp & (GS_HST_STS | GS_SMB_STS)) && (timeout++ < MAX_TIMEOUT)); /* If the SMBus is still busy, we give up */ - if (timeout >= MAX_TIMEOUT) { + if (timeout > MAX_TIMEOUT) { dev_dbg(&adap->dev, "Busy wait timeout (%04x)\n", temp); goto abort; } @@ -143,7 +143,7 @@ static int amd756_transaction(struct i2c_adapter *adap) } while ((temp & GS_HST_STS) && (timeout++ < MAX_TIMEOUT)); /* If the SMBus is still busy, we give up */ - if (timeout >= MAX_TIMEOUT) { + if (timeout > MAX_TIMEOUT) { dev_dbg(&adap->dev, "Completion timeout!\n"); goto abort; } diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 10411848fd7..9d2c5adf5d4 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -237,7 +237,7 @@ static int i801_transaction(int xact) status = inb_p(SMBHSTSTS); } while ((status & SMBHSTSTS_HOST_BUSY) && (timeout++ < MAX_TIMEOUT)); - result = i801_check_post(status, timeout >= MAX_TIMEOUT); + result = i801_check_post(status, timeout > MAX_TIMEOUT); if (result < 0) return result; @@ -257,9 +257,9 @@ static void i801_wait_hwpec(void) } while ((!(status & SMBHSTSTS_INTR)) && (timeout++ < MAX_TIMEOUT)); - if (timeout >= MAX_TIMEOUT) { + if (timeout > MAX_TIMEOUT) dev_dbg(&I801_dev->dev, "PEC Timeout!\n"); - } + outb_p(status, SMBHSTSTS); } @@ -344,7 +344,7 @@ static int i801_block_transaction_byte_by_byte(union i2c_smbus_data *data, while ((!(status & SMBHSTSTS_BYTE_DONE)) && (timeout++ < MAX_TIMEOUT)); - result = i801_check_post(status, timeout >= MAX_TIMEOUT); + result = i801_check_post(status, timeout > MAX_TIMEOUT); if (result < 0) return result; diff --git a/drivers/i2c/busses/i2c-isch.c b/drivers/i2c/busses/i2c-isch.c index b9c01aa9003..9f6b8e0f863 100644 --- a/drivers/i2c/busses/i2c-isch.c +++ b/drivers/i2c/busses/i2c-isch.c @@ -112,7 +112,7 @@ static int sch_transaction(void) } while ((temp & 0x08) && (timeout++ < MAX_TIMEOUT)); /* If the SMBus is still busy, we give up */ - if (timeout >= MAX_TIMEOUT) { + if (timeout > MAX_TIMEOUT) { dev_err(&sch_adapter.dev, "SMBus Timeout!\n"); result = -ETIMEDOUT; } diff --git a/drivers/i2c/busses/i2c-nforce2.c b/drivers/i2c/busses/i2c-nforce2.c index 2ff4683703a..ec11d1c4e77 100644 --- a/drivers/i2c/busses/i2c-nforce2.c +++ b/drivers/i2c/busses/i2c-nforce2.c @@ -173,7 +173,7 @@ static int nforce2_check_status(struct i2c_adapter *adap) temp = inb_p(NVIDIA_SMB_STS); } while ((!temp) && (timeout++ < MAX_TIMEOUT)); - if (timeout >= MAX_TIMEOUT) { + if (timeout > MAX_TIMEOUT) { dev_dbg(&adap->dev, "SMBus Timeout!\n"); if (smbus->can_abort) nforce2_abort(adap); diff --git a/drivers/i2c/busses/i2c-sis5595.c b/drivers/i2c/busses/i2c-sis5595.c index f320ab27da4..139f0c7f12a 100644 --- a/drivers/i2c/busses/i2c-sis5595.c +++ b/drivers/i2c/busses/i2c-sis5595.c @@ -256,7 +256,7 @@ static int sis5595_transaction(struct i2c_adapter *adap) } while (!(temp & 0x40) && (timeout++ < MAX_TIMEOUT)); /* If the SMBus is still busy, we give up */ - if (timeout >= MAX_TIMEOUT) { + if (timeout > MAX_TIMEOUT) { dev_dbg(&adap->dev, "SMBus Timeout!\n"); result = -ETIMEDOUT; } diff --git a/drivers/i2c/busses/i2c-sis630.c b/drivers/i2c/busses/i2c-sis630.c index 50c3610e602..70ca41e90e5 100644 --- a/drivers/i2c/busses/i2c-sis630.c +++ b/drivers/i2c/busses/i2c-sis630.c @@ -173,7 +173,7 @@ static int sis630_transaction_wait(struct i2c_adapter *adap, int size) } while (!(temp & 0x0e) && (timeout++ < MAX_TIMEOUT)); /* If the SMBus is still busy, we give up */ - if (timeout >= MAX_TIMEOUT) { + if (timeout > MAX_TIMEOUT) { dev_dbg(&adap->dev, "SMBus Timeout!\n"); result = -ETIMEDOUT; } diff --git a/drivers/i2c/busses/i2c-sis96x.c b/drivers/i2c/busses/i2c-sis96x.c index 7e1594b4057..8295885b2fd 100644 --- a/drivers/i2c/busses/i2c-sis96x.c +++ b/drivers/i2c/busses/i2c-sis96x.c @@ -132,7 +132,7 @@ static int sis96x_transaction(int size) } while (!(temp & 0x0e) && (timeout++ < MAX_TIMEOUT)); /* If the SMBus is still busy, we give up */ - if (timeout >= MAX_TIMEOUT) { + if (timeout > MAX_TIMEOUT) { dev_dbg(&sis96x_adapter.dev, "SMBus Timeout! (0x%02x)\n", temp); result = -ETIMEDOUT; } From 0cdba07bb23cdd3e0d64357ec3d983e6b75e541f Mon Sep 17 00:00:00 2001 From: Dave Airlie Date: Tue, 5 May 2009 08:39:24 +0200 Subject: [PATCH 2/3] i2c-algo-bit: Fix timeout test When fetching DDC using i2c algo bit, we were often seeing timeouts before getting valid EDID on a retry. The VESA spec states 2ms is the DDC timeout, so when this translates into 1 jiffie and we are close to the end of the time period, it could return with a timeout less than 2ms. Change this code to use time_after instead of time_after_eq. Signed-off-by: Dave Airlie Signed-off-by: Jean Delvare --- drivers/i2c/algos/i2c-algo-bit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c index d420cc5f563..e25e13980af 100644 --- a/drivers/i2c/algos/i2c-algo-bit.c +++ b/drivers/i2c/algos/i2c-algo-bit.c @@ -104,7 +104,7 @@ static int sclhi(struct i2c_algo_bit_data *adap) * chips may hold it low ("clock stretching") while they * are processing data internally. */ - if (time_after_eq(jiffies, start + adap->timeout)) + if (time_after(jiffies, start + adap->timeout)) return -ETIMEDOUT; cond_resched(); } From 2196d1cf4afab93fb64c2e5b417096e49b661612 Mon Sep 17 00:00:00 2001 From: Enrik Berkhan Date: Tue, 5 May 2009 08:39:25 +0200 Subject: [PATCH 3/3] i2c-algo-pca: Let PCA9564 recover from unacked data byte (state 0x30) Currently, the i2c-algo-pca driver does nothing if the chip enters state 0x30 (Data byte in I2CDAT has been transmitted; NOT ACK has been received). Thus, the i2c bus connected to the controller gets stuck afterwards. I have seen this kind of error on a custom board in certain load situations most probably caused by interference or noise. A possible reaction is to let the controller generate a STOP condition. This is documented in the PCA9564 data sheet (2006-09-01) and the same is done for other NACK states as well. Further, state 0x38 isn't handled completely, either. Try to do another START in this case like the data sheet says. As this couldn't be tested, I've added a comment to try to reset the chip if the START doesn't help as suggested by Wolfram Sang. Signed-off-by: Enrik Berkhan Reviewed-by: Wolfram Sang Signed-off-by: Jean Delvare --- drivers/i2c/algos/i2c-algo-pca.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c index 6318f7ddc1d..78d42aae008 100644 --- a/drivers/i2c/algos/i2c-algo-pca.c +++ b/drivers/i2c/algos/i2c-algo-pca.c @@ -287,10 +287,21 @@ static int pca_xfer(struct i2c_adapter *i2c_adap, case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */ DEB2("NOT ACK received after data byte\n"); + pca_stop(adap); goto out; case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */ DEB2("Arbitration lost\n"); + /* + * The PCA9564 data sheet (2006-09-01) says "A + * START condition will be transmitted when the + * bus becomes free (STOP or SCL and SDA high)" + * when the STA bit is set (p. 11). + * + * In case this won't work, try pca_reset() + * instead. + */ + pca_start(adap); goto out; case 0x58: /* Data byte has been received; NOT ACK has been returned */