[GitHub] [incubator-nuttx] anjiahao1 commented on pull request #6965: nxmutex replace nxsem when used as a lock

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anjiahao1 commented on PR #6965:
URL: https://github.com/apache/incubator-nuttx/pull/6965#issuecomment-1292927563

   Sorry, I'll check all the SEM modifications later.
   
   > Hi @anjiahao1 BL602 I2C Read seems to hang after this commit, I think it might be caused by the Semaphore Init Value.
   > 
   > Refer to the changes for `arch/risc-v/src/bl602/bl602_i2c.c`:
   > 
   > [d1d4633#diff-b9e7242d24fc5f206885bdcd9fa90409e9c8356d041a968e786cfb8c8db32aeb](https://github.com/apache/incubator-nuttx/commit/d1d46335df6cc1bc63f1cd7e7bffe3735b8c275d#diff-b9e7242d24fc5f206885bdcd9fa90409e9c8356d041a968e786cfb8c8db32aeb)
   > 
   > Previously the Semaphore `sem_isr` was set to Init Value 1:
   > 
   > ```c
   > static void bl602_i2c_sem_init(struct bl602_i2c_priv_s *priv)
   > {
   >   ...
   >   nxsem_init(&priv->sem_isr, 0, 1);
   > ```
   > 
   > Now `sem_isr` is set to Init Value 0:
   > 
   > ```c
   > static struct bl602_i2c_priv_s bl602_i2c0_priv =
   > {
   >   ...
   >   .sem_isr  = SEM_INITIALIZER(0),
   > ```
   > 
   > This causes [`nxsem_wait_uninterruptible`](https://github.com/apache/incubator-nuttx/blob/master/arch/risc-v/src/bl602/bl602_i2c.c#L682) to hang during I2C Transfer:
   > 
   > ```c
   > static int bl602_i2c_transfer(struct i2c_master_s *dev,
   >                               struct i2c_msg_s *   msgs,
   >                               int                      count)
   > {
   >   ...
   >   // Hangs here
   >   ret = nxsem_wait_uninterruptible(&priv->sem_isr);
   > ```
   > 
   > When I changed `sem_isr` to Init Value 1:
   > 
   > ```c
   >   .sem_isr  = SEM_INITIALIZER(1),
   > ```
   > 
   > The I2C Transfer now works OK. [(Here's the log)](https://github.com/lupyuen/incubator-nuttx/pull/148#issue-1421797837)
   > 
   > Can you verify if this fix `SEM_INITIALIZER(1)` is correct? Thanks :-)
   
   Sorry, I'll check all the SEM modifications later.


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