Albert Lee wrote:
Recently the PLL input clock of pata_pdc2027x is sometimes detected higer than expected (e.g. 20.027 MHz compared to 16.714 MHz). It seems sometimes the mdelay() function is not as precise as it used to be. Per Alan's advice, HT or power management might affect the precision of mdelay(). This patch calls gettimeofday() to mesure the time elapsed and calculate the PLL input clock accordingly. Signed-off-by: Albert Lee <albertcc@xxxxxxxxxx> Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> --- Did more test. For mdelay(100) the usec_elapsed is usually 99287. However, sometimes the usec_elapsed is 118934, longer than expected. Jun 26 12:12:29 p4ht-s kernel: [ 9156.490991] ACPI: PCI Interrupt 0000:02:05.0[A] -> Link [LNK1] -> GSI 10 (level, low) -> IRQ 10 Jun 26 12:12:29 p4ht-s kernel: [ 9156.610175] usec_elapsed[118934] Jun 26 12:12:29 p4ht-s kernel: [ 9156.610511] pata_pdc2027x 0000:02:05.0: PLL input clock 16817 kHz After the patch, the PLL input clock detected looks more accurate. For your review, thanks.
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